diff --git a/radio/src/CMakeLists.txt b/radio/src/CMakeLists.txt
index 739ec570880..d40887daca5 100644
--- a/radio/src/CMakeLists.txt
+++ b/radio/src/CMakeLists.txt
@@ -484,9 +484,16 @@ if(NATIVE_BUILD)
     ${RADIOLIB_NATIVE_SRC}
   )
 
-  # Add -DSIMU here PUBLIC, so it can be imported by other targets
+  # Add SIMU and POSIX_THREAD here PUBLIC, so it can be imported by other targets
   # via INTERFACE_COMPILE_OPTIONS
-  target_compile_options(radiolib_native PUBLIC -DSIMU)
+  target_compile_options(radiolib_native PUBLIC -DSIMU -DPOSIX_THREADS)
+  target_sources(radiolib_native PUBLIC
+    os/async_native.cpp
+    os/sleep_native.cpp
+    os/task_pthread.cpp
+    os/time_native.cpp
+    os/timer_pthread.cpp
+  )
   add_dependencies(radiolib_native ${RADIO_DEPENDENCIES})
   set_property(TARGET radiolib_native PROPERTY POSITION_INDEPENDENT_CODE ON)
 
@@ -554,13 +561,23 @@ if(BOOTLOADER)
   set(RADIO_DEPENDENCIES ${RADIO_DEPENDENCIES} bootloader)
 endif()
 
-add_definitions(-DFREE_RTOS)
-
 add_executable(firmware ${SRC})
 link_libraries(firmware -lstdc++)
 add_dependencies(firmware ${RADIO_DEPENDENCIES})
 set_target_properties(firmware PROPERTIES EXCLUDE_FROM_ALL TRUE)
 
+target_compile_definitions(board PUBLIC FREE_RTOS)
+target_compile_definitions(board_lib PUBLIC FREE_RTOS)
+target_compile_definitions(firmware PUBLIC FREE_RTOS)
+
+target_sources(firmware PUBLIC
+  os/async_freertos.cpp
+  os/sleep_freertos.cpp
+  os/task_freertos.cpp
+  os/time_freertos.cpp
+  os/timer_freertos.cpp
+)
+
 if(DEBUG)
   target_compile_definitions(board PRIVATE -DDEBUG)
   target_compile_definitions(firmware PRIVATE -DDEBUG)
diff --git a/radio/src/audio.cpp b/radio/src/audio.cpp
index ce299856d9c..9d9e24873ea 100644
--- a/radio/src/audio.cpp
+++ b/radio/src/audio.cpp
@@ -21,6 +21,9 @@
 
 #include <math.h>
 
+#include "os/sleep.h"
+#include "os/task.h"
+
 #include "edgetx.h"
 #include "strhelpers.h"
 #include "switches.h"
@@ -32,7 +35,7 @@
 #include "model_audio.h"
 #include "hal/audio_driver.h"
 
-extern RTOS_MUTEX_HANDLE audioMutex;
+extern mutex_handle_t audioMutex;
 
 // Only first quadrant values - other quadrants calulated taking advantage of symmetry in sine wave.
 const int16_t sineValues[] =
@@ -373,28 +376,6 @@ AudioQueue::AudioQueue()
 
 #define CODEC_ID_PCM_S16LE  1
 
-#if !defined(SIMU)
-void audioTask(void * pdata)
-{
-  while (!audioQueue.started()) {
-    RTOS_WAIT_TICKS(1);
-  }
-
-#if defined(PCBX12S) || defined(RADIO_TX16S) || defined(RADIO_F16) || defined(RADIO_V16)
-  // The audio amp needs ~2s to start
-  RTOS_WAIT_MS(1000); // 1s
-#endif
-
-  while (true) {
-    DEBUG_TIMER_SAMPLE(debugTimerAudioIterval);
-    DEBUG_TIMER_START(debugTimerAudioDuration);
-    audioQueue.wakeup();
-    DEBUG_TIMER_STOP(debugTimerAudioDuration);
-    RTOS_WAIT_MS(4); // ???
-  }
-}
-#endif
-
 #if !defined(__SSAT)
   #define _sat_s16(x) ((int16_t)limit<int32_t>(INT16_MIN, (x), INT16_MAX))
 #else
@@ -638,9 +619,9 @@ void AudioQueue::wakeup()
 
     // mix the normal context (tones and wavs)
     if (normalContext.isEmpty() && !fragmentsFifo.empty()) {
-      RTOS_LOCK_MUTEX(audioMutex);
+      mutex_lock(&audioMutex);
       normalContext.setFragment(fragmentsFifo.get());
-      RTOS_UNLOCK_MUTEX(audioMutex);
+      mutex_unlock(&audioMutex);
     }
     result = normalContext.mixBuffer(buffer, g_eeGeneral.beepVolume, g_eeGeneral.wavVolume, fade);
     if (result > 0) {
@@ -724,7 +705,7 @@ void AudioQueue::playTone(uint16_t freq, uint16_t len, uint16_t pause, uint8_t f
   return;
 #endif
 
-  RTOS_LOCK_MUTEX(audioMutex);
+  mutex_lock(&audioMutex);
 
   freq = limit<uint16_t>(BEEP_MIN_FREQ, freq, BEEP_MAX_FREQ);
 
@@ -747,7 +728,7 @@ void AudioQueue::playTone(uint16_t freq, uint16_t len, uint16_t pause, uint8_t f
     }
   }
 
-  RTOS_UNLOCK_MUTEX(audioMutex);
+  mutex_unlock(&audioMutex);
 }
 
 void AudioQueue::playFile(const char * filename, uint8_t flags, uint8_t id, int8_t fragmentVolume)
@@ -774,7 +755,7 @@ void AudioQueue::playFile(const char * filename, uint8_t flags, uint8_t id, int8
     return;
   }
 
-  RTOS_LOCK_MUTEX(audioMutex);
+  mutex_lock(&audioMutex);
 
   if (flags & PLAY_BACKGROUND) {
     backgroundContext.clear();
@@ -784,7 +765,7 @@ void AudioQueue::playFile(const char * filename, uint8_t flags, uint8_t id, int8
     fragmentsFifo.push(AudioFragment(filename, flags & 0x0f, fragmentVolume, id));
   }
 
-  RTOS_UNLOCK_MUTEX(audioMutex);
+  mutex_unlock(&audioMutex);
 }
 
 void AudioQueue::stopPlay(uint8_t id)
@@ -797,12 +778,12 @@ void AudioQueue::stopPlay(uint8_t id)
   return;
 #endif
 
-  RTOS_LOCK_MUTEX(audioMutex);
+  mutex_lock(&audioMutex);
 
   fragmentsFifo.removePromptById(id);
   backgroundContext.stop(id);
 
-  RTOS_UNLOCK_MUTEX(audioMutex);
+  mutex_unlock(&audioMutex);
 }
 
 void AudioQueue::stopSD()
@@ -815,19 +796,19 @@ void AudioQueue::stopSD()
 void AudioQueue::stopAll()
 {
   flush();
-  RTOS_LOCK_MUTEX(audioMutex);
+  mutex_lock(&audioMutex);
   priorityContext.clear();
   normalContext.clear();
-  RTOS_UNLOCK_MUTEX(audioMutex);
+  mutex_unlock(&audioMutex);
 }
 
 void AudioQueue::flush()
 {
-  RTOS_LOCK_MUTEX(audioMutex);
+  mutex_lock(&audioMutex);
   fragmentsFifo.clear();
   varioContext.clear();
   backgroundContext.clear();
-  RTOS_UNLOCK_MUTEX(audioMutex);
+  mutex_unlock(&audioMutex);
 }
 
 void audioPlay(unsigned int index, uint8_t id)
diff --git a/radio/src/audio.h b/radio/src/audio.h
index 0e987a6f674..f42e873e335 100644
--- a/radio/src/audio.h
+++ b/radio/src/audio.h
@@ -470,7 +470,6 @@ void codecsInit();
 void audioEvent(unsigned int index);
 void audioPlay(unsigned int index, uint8_t id=0);
 void audioStart();
-void audioTask(void * pdata);
 
 #if defined(AUDIO) && defined(BUZZER)
   #define AUDIO_BUZZER(a, b)  do { a; b; } while(0)
diff --git a/radio/src/bluetooth.cpp b/radio/src/bluetooth.cpp
index 5b77e72a176..8e64e99818e 100644
--- a/radio/src/bluetooth.cpp
+++ b/radio/src/bluetooth.cpp
@@ -23,6 +23,7 @@
 #include "edgetx.h"
 #include "io/frsky_firmware_update.h"
 #include "bluetooth_driver.h"
+#include "os/sleep.h"
 #include "trainer.h"
 
 #if defined(LIBOPENUI)
@@ -571,7 +572,7 @@ uint8_t Bluetooth::read(uint8_t * data, uint8_t size, uint32_t timeout)
       if (elapsed++ >= timeout) {
         return len;
       }
-      RTOS_WAIT_MS(1);
+      sleep_ms(1);
     }
     data[len++] = byte;
   }
@@ -829,11 +830,11 @@ const char * Bluetooth::flashFirmware(const char * filename, ProgressHandler pro
 
   bluetoothInit(BLUETOOTH_BOOTLOADER_BAUDRATE, true); // normal mode
   watchdogSuspend(500 /*5s*/);
-  RTOS_WAIT_MS(1000);
+  sleep_ms(1000);
 
   bluetoothInit(BLUETOOTH_BOOTLOADER_BAUDRATE, false); // bootloader mode
   watchdogSuspend(500 /*5s*/);
-  RTOS_WAIT_MS(1000);
+  sleep_ms(1000);
 
   const char * result = doFlashFirmware(filename, progressHandler);
 
@@ -851,7 +852,7 @@ const char * Bluetooth::flashFirmware(const char * filename, ProgressHandler pro
 
   /* wait 1s off */
   watchdogSuspend(500 /*5s*/);
-  RTOS_WAIT_MS(1000);
+  sleep_ms(1000);
 
   state = BLUETOOTH_STATE_OFF;
   pulsesStart();
diff --git a/radio/src/boards/generic_stm32/rgb_leds.cpp b/radio/src/boards/generic_stm32/rgb_leds.cpp
index e93f4c8c003..d928d623167 100644
--- a/radio/src/boards/generic_stm32/rgb_leds.cpp
+++ b/radio/src/boards/generic_stm32/rgb_leds.cpp
@@ -30,18 +30,13 @@
 #include "stm32_dma.h"
 #include "stm32_gpio.h"
 #include "hal/gpio.h"
-
-#if !defined(SIMU)
-#include <FreeRTOS/include/FreeRTOS.h>
-#include <FreeRTOS/include/timers.h>
-#endif
+#include "os/timer.h"
 
 static uint8_t _led_colors[WS2812_BYTES_PER_LED * LED_STRIP_LENGTH];
 
 extern const stm32_pulse_timer_t _led_timer;
 
-static TimerHandle_t rgbLedTimer = nullptr;
-static StaticTimer_t rgbLedTimerBuffer;
+static timer_handle_t _refresh_timer = TIMER_INITIALIZER;
 
 void rgbSetLedColor(uint8_t led, uint8_t r, uint8_t g, uint8_t b)
 {
@@ -77,35 +72,25 @@ void rgbLedClearAll()
   ws2812_update(&_led_timer);
 }
 
-static void rgbLedTimerCb(TimerHandle_t xTimer)
+static void _refresh_cb(timer_handle_t* timer)
 {
-  (void)xTimer;
-
+  (void)timer;
   ws2812_update(&_led_timer);
 }
 
 void rgbLedStart()
 {
-  if (!rgbLedTimer) {
-    rgbLedTimer =
-        xTimerCreateStatic("rgbLed", LED_STRIP_REFRESH_PERIOD / RTOS_MS_PER_TICK, pdTRUE, (void*)0,
-                           rgbLedTimerCb, &rgbLedTimerBuffer);
+  if (!timer_is_created(&_refresh_timer)) {
+    timer_create(&_refresh_timer, _refresh_cb, "rgbled",
+                 LED_STRIP_REFRESH_PERIOD, true);
   }
 
-  if (rgbLedTimer) {
-    if( xTimerStart( rgbLedTimer, 0 ) != pdPASS ) {
-      /* The timer could not be set into the Active state. */
-    }
-  }
+  timer_start(&_refresh_timer);
 }
 
 void rgbLedStop()
 {
-  if (rgbLedTimer) {
-    if( xTimerStop( rgbLedTimer, 5 / RTOS_MS_PER_TICK ) != pdPASS ) {
-      /* The timer could not be stopped. */
-    }
-  }
+  timer_stop(&_refresh_timer);
 }
 
 const stm32_pulse_timer_t _led_timer = {
diff --git a/radio/src/cli.cpp b/radio/src/cli.cpp
index 108b9dc9b96..5872c743c24 100644
--- a/radio/src/cli.cpp
+++ b/radio/src/cli.cpp
@@ -32,6 +32,9 @@
 #include "hal/watchdog_driver.h"
 
 #include "edgetx.h"
+#include "os/sleep.h"
+#include "os/time.h"
+#include "os/task.h"
 #include "timers_driver.h"
 
 #if defined(BLUETOOTH)
@@ -58,8 +61,8 @@
 
 #define CLI_PRINT_BUFFER_SIZE 128
 
-RTOS_TASK_HANDLE cliTaskId;
-RTOS_DEFINE_STACK(cliTaskId, cliStack, CLI_STACK_SIZE);
+task_handle_t cliTaskId;
+TASK_DEFINE_STACK(cliStack, CLI_STACK_SIZE);
 
 static uint8_t cliRxBufferStorage[CLI_RX_BUFFER_SIZE];
 static StaticStreamBuffer_t cliRxBufferStatic;
@@ -188,9 +191,9 @@ static uint32_t cliGetBaudRate()
 char cliLastLine[CLI_COMMAND_MAX_LEN+1];
 
 typedef int (* CliFunction) (const char ** args);
-int cliExecLine(char * line);
-int cliExecCommand(const char ** argv);
-int cliHelp(const char ** argv);
+static int cliExecLine(char * line);
+static int cliExecCommand(const char ** argv);
+static int cliHelp(const char ** argv);
 
 struct CliCommand
 {
@@ -466,7 +469,7 @@ int cliTestNew()
 {
   char * tmp = nullptr;
   cliSerialPrint("Allocating 1kB with new()");
-  RTOS_WAIT_MS(200);
+  sleep_ms(200);
   tmp = new char[1024];
   if (tmp) {
     cliSerialPrint("\tsuccess");
@@ -478,7 +481,7 @@ int cliTestNew()
   }
 
   cliSerialPrint("Allocating 10MB with (std::nothrow) new()");
-  RTOS_WAIT_MS(200);
+  sleep_ms(200);
   tmp = new (std::nothrow) char[1024*1024*10];
   if (tmp) {
     cliSerialPrint("\tFAILURE, tmp = %p", tmp);
@@ -490,7 +493,7 @@ int cliTestNew()
   }
 
   cliSerialPrint("Allocating 10MB with new()");
-  RTOS_WAIT_MS(200);
+  sleep_ms(200);
   tmp = new char[1024*1024*10];
   if (tmp) {
     cliSerialPrint("\tFAILURE, tmp = %p", tmp);
@@ -569,10 +572,10 @@ void testClear() { lcdClear(); }
 float runTimedFunctionTest(timedTestFunc_t func, const char *name,
                            uint32_t runtime, uint16_t step)
 {
-  const uint32_t start = RTOS_GET_MS();
+  const uint32_t start = time_get_ms();
   uint32_t noRuns = 0;
   uint32_t actualRuntime = 0;
-  while ((actualRuntime = RTOS_GET_MS() - start) < runtime) {
+  while ((actualRuntime = time_get_ms() - start) < runtime) {
     for (uint16_t n = 0; n < step; n++) {
       func();
     }
@@ -583,14 +586,14 @@ float runTimedFunctionTest(timedTestFunc_t func, const char *name,
   cliSerialPrint("Test %s speed: %lu.%02u, (%lu runs in %lu ms)", name,
               uint32_t(result), uint16_t((result - uint32_t(result)) * 100.0f),
               noRuns, actualRuntime);
-  RTOS_WAIT_MS(200);
+  sleep_ms(200);
   return result;
 }
 
 int cliTestGraphics()
 {
   cliSerialPrint("Starting graphics performance test...");
-  RTOS_WAIT_MS(200);
+  sleep_ms(200);
 
   watchdogSuspend(6000 /*60s*/);
   if (pulsesStarted()) {
@@ -723,7 +726,7 @@ void testMemoryCopyFrom_SDRAM_to_SDRAM_8bit()
 int cliTestMemorySpeed()
 {
   cliSerialPrint("Starting memory speed test...");
-  RTOS_WAIT_MS(200);
+  sleep_ms(200);
 
   watchdogSuspend(6000 /*60s*/);
   if (pulsesStarted()) {
@@ -744,7 +747,7 @@ int cliTestMemorySpeed()
 
   LTDC_Cmd(DISABLE);
   cliSerialPrint("Disabling LCD...");
-  RTOS_WAIT_MS(200);
+  sleep_ms(200);
 
   result += RUN_MEMORY_TEST(testMemoryReadFrom_RAM_8bit, 200);
   result += RUN_MEMORY_TEST(testMemoryReadFrom_RAM_32bit, 200);
@@ -783,7 +786,7 @@ int cliTestModelsList()
   int count = 0;
 
   cliSerialPrint("Starting fetching RF data 100x...");
-  const uint32_t start = RTOS_GET_MS();
+  const uint32_t start = time_get_ms();
 
   const list<ModelsCategory *> &cats = modList.getCategories();
   while (1) {
@@ -803,7 +806,7 @@ int cliTestModelsList()
 
 done:
   cliSerialPrint("Done fetching %ix RF data: %lu ms", count,
-              (RTOS_GET_MS() - start));
+              (time_get_ms() - start));
 
   return 0;
 }
@@ -1474,7 +1477,7 @@ int cliRepeat(const char ** argv)
     counter = interval;
 
     uint8_t c;
-    const TickType_t xTimeout = 20 / RTOS_MS_PER_TICK;
+    const TickType_t xTimeout = 20 / portTICK_PERIOD_MS;
     while (!xStreamBufferReceive(cliRxBuffer, &c, 1, xTimeout)
            || !(c == '\r' || c == '\n' || c == ' ')) {
 
@@ -1610,9 +1613,9 @@ int cliCrypt(const char ** argv)
   mixerTaskStop();
   perMainEnabled = false;
 
-  uint32_t startMs = RTOS_GET_MS();
+  uint32_t startMs = time_get_ms();
   testAccessDenied(100000);
-  cliSerialPrintf("access_denied: %f us/run\r\n", (RTOS_GET_MS() - startMs)*1000.0f / 100000.0f);
+  cliSerialPrintf("access_denied: %f us/run\r\n", (time_get_ms() - startMs)*1000.0f / 100000.0f);
 
   cliSerialPrint("Decrypted (SW):");
   dumpBody(cryptOutput, sizeof(cryptOutput));
@@ -1706,7 +1709,7 @@ const CliCommand cliCommands[] = {
   { nullptr, nullptr, nullptr }  /* sentinel */
 };
 
-int cliHelp(const char ** argv)
+static int cliHelp(const char ** argv)
 {
   for (const CliCommand * command = cliCommands; command->name != nullptr; command++) {
     if (argv[1][0] == '\0' || !strcmp(command->name, argv[0])) {
@@ -1722,7 +1725,7 @@ int cliHelp(const char ** argv)
   return -1;
 }
 
-int cliExecCommand(const char ** argv)
+static int cliExecCommand(const char ** argv)
 {
   if (argv[0][0] == '\0')
     return 0;
@@ -1736,7 +1739,7 @@ int cliExecCommand(const char ** argv)
   return -1;
 }
 
-int cliExecLine(char * line)
+static int cliExecLine(char * line)
 {
   int len = strlen(line);
   const char * argv[CLI_COMMAND_MAX_ARGS];
@@ -1759,7 +1762,7 @@ int cliExecLine(char * line)
 #define CHAR_CR         0x0D
 #define CHAR_DEL        0x7F
 
-void cliTask(void * pdata)
+static void cliTask()
 {
   char line[CLI_COMMAND_MAX_LEN+1];
   int pos = 0;
@@ -1773,7 +1776,7 @@ void cliTask(void * pdata)
     //       of going byte-by-byte.
     
     /* Block for max 100ms. */
-    const TickType_t xTimeout = 100 / RTOS_MS_PER_TICK;
+    const TickType_t xTimeout = 100 / portTICK_PERIOD_MS;
     size_t xReceivedBytes = xStreamBufferReceive(cliRxBuffer, &c, 1, xTimeout);
 
     if (!mixerTaskRunning()) {
@@ -1811,8 +1814,7 @@ void cliTask(void * pdata)
       if (pos == 0 && cliLastLine[0]) {
         // execute (repeat) last command
         strcpy(line, cliLastLine);
-      }
-      else {
+      } else {
         // save new command
         strcpy(cliLastLine, line);
       }
@@ -1843,6 +1845,6 @@ void cliStart()
   // Setup consumer callback
   cliReceiveCallBack = cliDefaultRx;
 
-  RTOS_CREATE_TASK(cliTaskId, cliTask, "CLI", cliStack, CLI_STACK_SIZE,
-                   CLI_TASK_PRIO);
+  task_create(&cliTaskId, cliTask, "CLI", cliStack, CLI_STACK_SIZE,
+              CLI_TASK_PRIO);
 }
diff --git a/radio/src/edgetx.cpp b/radio/src/edgetx.cpp
index 05421d6ae0b..4b48890e17a 100644
--- a/radio/src/edgetx.cpp
+++ b/radio/src/edgetx.cpp
@@ -19,6 +19,7 @@
  * GNU General Public License for more details.
  */
 
+#include "os/sleep.h"
 #if !defined(SIMU)
 #include "stm32_ws2812.h"
 #include "boards/generic_stm32/rgb_leds.h"
@@ -45,6 +46,7 @@
 
 #include "tasks.h"
 #include "tasks/mixer_task.h"
+#include "os/async.h"
 
 #if defined(BLUETOOTH)
   #include "bluetooth_driver.h"
@@ -167,7 +169,7 @@ void checkValidMCU(void)
 static bool evalFSok = false;
 #endif
 
-void timer_10ms()
+void per10ms()
 {
   DEBUG_TIMER_START(debugTimerPer10ms);
   DEBUG_TIMER_SAMPLE(debugTimerPer10msPeriod);
@@ -245,44 +247,6 @@ void timer_10ms()
   DEBUG_TIMER_STOP(debugTimerPer10ms);
 }
 
-#if !defined(SIMU)
-// Handle 10ms timer asynchronously
-#include <FreeRTOS/include/FreeRTOS.h>
-#include <FreeRTOS/include/timers.h>
-
-static volatile bool _timer_10ms_cb_in_queue = false;
-
-static void _timer_10ms_cb(void *pvParameter1, uint32_t ulParameter2)
-{
-  (void)pvParameter1;
-  (void)ulParameter2;
-  _timer_10ms_cb_in_queue = false;
-  timer_10ms();
-}
-
-void per10ms()
-{
-
-  if (!_timer_10ms_cb_in_queue && xTaskGetSchedulerState() != taskSCHEDULER_NOT_STARTED) {
-    BaseType_t xHigherPriorityTaskWoken = pdFALSE;
-    BaseType_t xReturn = pdFALSE;
-
-    xReturn = xTimerPendFunctionCallFromISR(_timer_10ms_cb, nullptr, 0, &xHigherPriorityTaskWoken);
-
-    if (xReturn == pdPASS) {
-      _timer_10ms_cb_in_queue = true;
-    } else {
-      TRACE("xTimerPendFunctionCallFromISR() queue full");
-    }
-    portYIELD_FROM_ISR( xHigherPriorityTaskWoken );
-  }
-}
-
-#else // !defined(SIMU)
-void per10ms() { timer_10ms(); }
-#endif
-
-
 FlightModeData *flightModeAddress(uint8_t idx)
 {
   return &g_model.flightModeData[idx];
@@ -757,7 +721,7 @@ void checkAll(bool isBootCheck)
     showMessageBox(STR_KEYSTUCK);
     tmr10ms_t tgtime = get_tmr10ms() + 500;
     while (tgtime != get_tmr10ms()) {
-      RTOS_WAIT_MS(1);
+      sleep_ms(1);
       WDG_RESET();
     }
   }
@@ -875,8 +839,7 @@ void checkThrottleStick()
     checkBacklight();
 
     WDG_RESET();
-
-    RTOS_WAIT_MS(10);
+    sleep_ms(10);
   }
 
   LED_ERROR_END();
@@ -907,7 +870,7 @@ void alert(const char * title, const char * msg , uint8_t sound)
 #endif
 
   while (true) {
-    RTOS_WAIT_MS(10);
+    sleep_ms(10);
 
     if (getEvent())  // wait for key release
       break;
@@ -1131,10 +1094,10 @@ void edgeTxClose(uint8_t shutdown)
   storageCheck(true);
 
   while (IS_PLAYING(ID_PLAY_PROMPT_BASE + AU_BYE)) {
-    RTOS_WAIT_MS(10);
+    sleep_ms(10);
   }
 
-  RTOS_WAIT_MS(100);
+  sleep_ms(100);
 
 #if defined(COLORLCD)
   cancelShutdownAnimation();  // To prevent simulator crash
@@ -1887,7 +1850,7 @@ uint32_t pwrCheck()
       RAISE_ALERT(STR_MODEL, STR_MODEL_STILL_POWERED, STR_PRESS_ENTER_TO_CONFIRM, AU_MODEL_STILL_POWERED);
       while (TELEMETRY_STREAMING()) {
         resetForcePowerOffRequest();
-        RTOS_WAIT_MS(20);
+        sleep_ms(20);
         if (pwrPressed()) {
           return e_power_on;
         }
diff --git a/radio/src/gui/128x64/view_statistics.cpp b/radio/src/gui/128x64/view_statistics.cpp
index f37b6a55fa5..1b952909228 100644
--- a/radio/src/gui/128x64/view_statistics.cpp
+++ b/radio/src/gui/128x64/view_statistics.cpp
@@ -21,7 +21,9 @@
 
 #include "edgetx.h"
 #include "tasks.h"
+
 #include "mixer_scheduler.h"
+#include "tasks/mixer_task.h"
 
 #include "hal/adc_driver.h"
 
@@ -169,12 +171,12 @@ void menuStatisticsDebug(event_t event)
   y += FH;
 
   lcdDrawTextAlignedLeft(y, STR_FREE_STACK);
-  lcdDrawNumber(MENU_DEBUG_COL1_OFS, y, menusStack.available(), LEFT);
+  lcdDrawNumber(MENU_DEBUG_COL1_OFS, y, task_get_stack_usage(&menusTaskId), LEFT);
   lcdDrawText(lcdLastRightPos, y, "/");
-  lcdDrawNumber(lcdLastRightPos, y, mixerStack.available(), LEFT);
+  lcdDrawNumber(lcdLastRightPos, y, task_get_stack_usage(&mixerTaskId), LEFT);
 #if defined(AUDIO)
   lcdDrawText(lcdLastRightPos, y, "/");
-  lcdDrawNumber(lcdLastRightPos, y, audioStack.available(), LEFT);
+  lcdDrawNumber(lcdLastRightPos, y, task_get_stack_usage(&audioTaskId), LEFT);
 #endif
   y += FH;
 
diff --git a/radio/src/gui/212x64/view_statistics.cpp b/radio/src/gui/212x64/view_statistics.cpp
index 4c892904ac3..93dfb4e08ea 100644
--- a/radio/src/gui/212x64/view_statistics.cpp
+++ b/radio/src/gui/212x64/view_statistics.cpp
@@ -21,7 +21,9 @@
 
 #include "hal/adc_driver.h"
 #include "edgetx.h"
+
 #include "tasks.h"
+#include "tasks/mixer_task.h"
 
 #define STATS_1ST_COLUMN               FW/2
 #define STATS_2ND_COLUMN               12*FW+FW/2
@@ -188,12 +190,12 @@ void menuStatisticsDebug(event_t event)
 
   lcdDrawTextAlignedLeft(y, STR_FREE_STACK);
   lcdDrawText(MENU_DEBUG_COL1_OFS, y+1, "[M]", SMLSIZE);
-  lcdDrawNumber(lcdLastRightPos, y, menusStack.available(), LEFT);
+  lcdDrawNumber(lcdLastRightPos, y, task_get_stack_usage(&menusTaskId), LEFT);
   lcdDrawText(lcdLastRightPos+2, y+1, "[X]", SMLSIZE);
-  lcdDrawNumber(lcdLastRightPos, y, mixerStack.available(), LEFT);
+  lcdDrawNumber(lcdLastRightPos, y, task_get_stack_usage(&mixerTaskId), LEFT);
 #if defined(AUDIO)
   lcdDrawText(lcdLastRightPos+2, y+1, "[A]", SMLSIZE);
-  lcdDrawNumber(lcdLastRightPos, y, audioStack.available(), LEFT);
+  lcdDrawNumber(lcdLastRightPos, y, task_get_stack_usage(&audioTaskId), LEFT);
 #endif
   lcdDrawText(lcdLastRightPos+2, y+1, "[I]", SMLSIZE);
   lcdDrawNumber(lcdLastRightPos, y, mainStackAvailable(), LEFT);
diff --git a/radio/src/gui/colorlcd/LvglWrapper.cpp b/radio/src/gui/colorlcd/LvglWrapper.cpp
index f44c8e5c7dd..81cf7038a73 100644
--- a/radio/src/gui/colorlcd/LvglWrapper.cpp
+++ b/radio/src/gui/colorlcd/LvglWrapper.cpp
@@ -21,6 +21,7 @@
 
 #include "edgetx.h"
 #include "hal/rotary_encoder.h"
+#include "os/time.h"
 
 #include "LvglWrapper.h"
 #include "etx_lv_theme.h"
@@ -359,9 +360,10 @@ LvglWrapper* LvglWrapper::instance()
 void LvglWrapper::run()
 {
 #if defined(SIMU)
-  tmr10ms_t tick = get_tmr10ms();
-  lv_tick_inc((tick - lastTick) * 10);
-  lastTick = tick;
+  static uint32_t last_tick = 0;
+  uint32_t tick = time_get_ms();
+  lv_tick_inc(tick - last_tick);
+  last_tick = tick;
 #endif
   lv_timer_handler();
 }
diff --git a/radio/src/gui/colorlcd/LvglWrapper.h b/radio/src/gui/colorlcd/LvglWrapper.h
index 2c50e50e8e8..b65732bd79e 100644
--- a/radio/src/gui/colorlcd/LvglWrapper.h
+++ b/radio/src/gui/colorlcd/LvglWrapper.h
@@ -33,9 +33,6 @@ class LvglWrapper
   static LvglWrapper *_instance;
   static void pollInputs();
 
-  tmr10ms_t lastTick = 0;
-  // TODO: add driver instances here
-
   LvglWrapper();
   ~LvglWrapper() {}
 
diff --git a/radio/src/gui/colorlcd/libui/fullscreen_dialog.cpp b/radio/src/gui/colorlcd/libui/fullscreen_dialog.cpp
index deb2e3efdb6..2c45a69287b 100644
--- a/radio/src/gui/colorlcd/libui/fullscreen_dialog.cpp
+++ b/radio/src/gui/colorlcd/libui/fullscreen_dialog.cpp
@@ -26,6 +26,7 @@
 #include "mainwindow.h"
 #include "edgetx.h"
 #include "etx_lv_theme.h"
+#include "os/sleep.h"
 #include "view_main.h"
 #include "hal/watchdog_driver.h"
 
@@ -186,7 +187,7 @@ static void run_ui_manually()
   checkBacklight();
   WDG_RESET();
 
-  RTOS_WAIT_MS(10);
+  sleep_ms(10);
   LvglWrapper::runNested();
   MainWindow::instance()->run(false);
 }
@@ -211,7 +212,7 @@ void FullScreenDialog::runForever(bool checkPwr)
 #endif
       } else if (check == e_power_press) {
         WDG_RESET();
-        RTOS_WAIT_MS(1);
+        sleep_ms(1);
         continue;
       }
     }
diff --git a/radio/src/gui/colorlcd/libui/popups.cpp b/radio/src/gui/colorlcd/libui/popups.cpp
index 131ba71b65a..14e284de181 100644
--- a/radio/src/gui/colorlcd/libui/popups.cpp
+++ b/radio/src/gui/colorlcd/libui/popups.cpp
@@ -23,6 +23,8 @@
 
 #include "libopenui.h"
 #include "edgetx.h"
+#include "lvgl/src/hal/lv_hal_tick.h"
+#include "os/sleep.h"
 #include "pwr.h"
 #include "hal/watchdog_driver.h"
 #include "etx_lv_theme.h"
@@ -51,7 +53,7 @@ static void _run_popup_dialog(const char* title, const char* msg,
 #endif
     } else if (check == e_power_press) {
       WDG_RESET();
-      RTOS_WAIT_MS(1);
+      sleep_ms(1);
       continue;
     }
 
@@ -59,7 +61,7 @@ static void _run_popup_dialog(const char* title, const char* msg,
     WDG_RESET();
     MainWindow::instance()->run();
     LvglWrapper::runNested();
-    RTOS_WAIT_MS(20);
+    sleep_ms(20);
   }
 }
 
@@ -95,7 +97,7 @@ void POPUP_WARNING_ON_UI_TASK(const char* message, const char* info,
 
   // Wait in case already in popup.
   while (ui_popup_active) {
-    RTOS_WAIT_MS(20);
+    sleep_ms(20);
   }
   ui_popup_title = "Warning";
   ui_popup_msg = message;
@@ -105,7 +107,7 @@ void POPUP_WARNING_ON_UI_TASK(const char* message, const char* info,
   // Wait until closed
   if (waitForClose) {
     while (ui_popup_active) {
-      RTOS_WAIT_MS(20);
+      sleep_ms(20);
     }
   }
 }
@@ -151,7 +153,8 @@ class BubbleDialog : public Window
  public:
   BubbleDialog(const char* message, int timeout, coord_t width) :
       Window(MainWindow::instance(), rect_t{(LCD_W - width) / 2, LCD_H - 100, width, 50},
-             bubble_popup_create)
+             bubble_popup_create),
+      startTime(lv_tick_get()), timeout(timeout)
   {
     setWindowFlag(OPAQUE);
 
@@ -163,21 +166,20 @@ class BubbleDialog : public Window
     lv_obj_set_width(label, lv_pct(100));
     etx_obj_add_style(label, styles->text_align_center, LV_PART_MAIN);
     lv_label_set_long_mode(label, LV_LABEL_LONG_WRAP);
-
-    endTime = RTOS_GET_MS() + timeout;
   }
 
   bool isBubblePopup() override { return true; }
 
   void checkEvents() override
   {
-    if (RTOS_GET_MS() >= endTime) {
+    if (lv_tick_elaps(startTime) >= timeout) {
       deleteLater();
     }
   }
 
  protected:
-  uint32_t endTime;
+  uint32_t startTime;
+  uint32_t timeout;
 };
 
 void POPUP_BUBBLE(const char* message, uint32_t timeout, coord_t width)
diff --git a/radio/src/gui/colorlcd/libui/tabsgroup.cpp b/radio/src/gui/colorlcd/libui/tabsgroup.cpp
index 4cf32d76078..6cb87cbb702 100644
--- a/radio/src/gui/colorlcd/libui/tabsgroup.cpp
+++ b/radio/src/gui/colorlcd/libui/tabsgroup.cpp
@@ -37,13 +37,13 @@ static bool timepg = false;
 static void on_draw_begin(lv_event_t* e)
 {
   if (timepg) {
-    dsms = RTOS_GET_MS();
+    dsms = lv_tick_get();
   }
 }
 static void on_draw_end(lv_event_t* e)
 {
   timepg = false;
-  dems = RTOS_GET_MS();
+  dems = lv_tick_get();
   TRACE("tab time: build %ld layout %ld draw %ld total %ld",
         end_ms - start_ms, dsms - end_ms, dems - dsms, dems - start_ms);
 }
@@ -301,7 +301,7 @@ void TabsGroup::setCurrentTab(unsigned index)
     currentTab = tab;
 
 #if defined(DEBUG)
-    start_ms = RTOS_GET_MS();
+    start_ms = lv_tick_get();
     timepg = true;
 #endif
 
@@ -321,7 +321,7 @@ void TabsGroup::setCurrentTab(unsigned index)
     lv_obj_refresh_style(body->getLvObj(), LV_PART_ANY, LV_STYLE_PROP_ANY);
 
 #if defined(DEBUG)
-    end_ms = RTOS_GET_MS();
+    end_ms = lv_tick_get();
 #endif
   }
 }
diff --git a/radio/src/gui/colorlcd/mainview/topbar_impl.cpp b/radio/src/gui/colorlcd/mainview/topbar_impl.cpp
index bd6b42564d3..ae4753d0030 100644
--- a/radio/src/gui/colorlcd/mainview/topbar_impl.cpp
+++ b/radio/src/gui/colorlcd/mainview/topbar_impl.cpp
@@ -114,7 +114,7 @@ coord_t TopBar::getVisibleHeight(float visible) const // 0.0 -> 1.0
 
 void TopBar::checkEvents()
 {
-  uint32_t now = RTOS_GET_MS();
+  uint32_t now = lv_tick_get();
   if (now - lastRefresh >= TOPBAR_REFRESH) {
     lastRefresh = now;
     TopBarBase::checkEvents();
diff --git a/radio/src/gui/colorlcd/mainview/view_statistics.cpp b/radio/src/gui/colorlcd/mainview/view_statistics.cpp
index 72a077fa936..700a64ad610 100644
--- a/radio/src/gui/colorlcd/mainview/view_statistics.cpp
+++ b/radio/src/gui/colorlcd/mainview/view_statistics.cpp
@@ -20,6 +20,7 @@
  */
 
 #include "view_statistics.h"
+#include "os/task.h"
 
 #include "edgetx.h"
 #include "tasks.h"
@@ -333,14 +334,14 @@ void DebugViewPage::build(Window* window)
 #endif
   new DebugInfoNumber<uint32_t>(
       line, rect_t{0, 0, DBG_B_WIDTH, DBG_B_HEIGHT},
-      [] { return menusStack.available(); }, STR_STACK_MENU);
+      [] { return task_get_stack_usage(&menusTaskId); }, STR_STACK_MENU);
   new DebugInfoNumber<uint32_t>(
       line, rect_t{0, 0, DBG_B_WIDTH, DBG_B_HEIGHT},
-      [] { return mixerStack.available(); }, STR_STACK_MIX);
+      [] { return task_get_stack_usage(&mixerTaskId); }, STR_STACK_MIX);
 #if defined(AUDIO)
   new DebugInfoNumber<uint32_t>(
       line, rect_t{0, 0, DBG_B_WIDTH, DBG_B_HEIGHT},
-      [] { return audioStack.available(); }, STR_STACK_AUDIO);
+      [] { return task_get_stack_usage(&audioTaskId); }, STR_STACK_AUDIO);
 #endif
 
 #if defined(DEBUG_LATENCY)
diff --git a/radio/src/gui/colorlcd/model/model_telemetry.cpp b/radio/src/gui/colorlcd/model/model_telemetry.cpp
index 93e8c83a053..d8e8670de47 100644
--- a/radio/src/gui/colorlcd/model/model_telemetry.cpp
+++ b/radio/src/gui/colorlcd/model/model_telemetry.cpp
@@ -367,7 +367,7 @@ class SensorButton : public ListLineButton
     else
       lv_obj_add_flag(fresh, LV_OBJ_FLAG_HIDDEN);
 
-    uint32_t now = RTOS_GET_MS();
+    uint32_t now = lv_tick_get();
     TelemetryItem& telemetryItem = telemetryItems[index];
 
     // Update value
@@ -479,7 +479,7 @@ class SensorEditWindow : public SubPage
 
   void checkEvents() override
   {
-    uint32_t now = RTOS_GET_MS();
+    uint32_t now = lv_tick_get();
     TelemetryItem& telemetryItem = telemetryItems[index];
 
     if ((now - lastRefresh >= 200) || telemetryItem.isFresh()) {
diff --git a/radio/src/gui/colorlcd/module/module_setup.cpp b/radio/src/gui/colorlcd/module/module_setup.cpp
index d648fa3a056..3c12a691488 100644
--- a/radio/src/gui/colorlcd/module/module_setup.cpp
+++ b/radio/src/gui/colorlcd/module/module_setup.cpp
@@ -609,8 +609,8 @@ class ModuleSubTypeChoice : public Choice
       MultiModuleStatus& status = getMultiModuleStatus(moduleIdx);
       status.invalidate();
 
-      uint32_t startUpdate = RTOS_GET_MS();
-      while (!status.isValid() && (RTOS_GET_MS() - startUpdate < 250))
+      uint32_t startUpdate = lv_tick_get();
+      while (!status.isValid() && (lv_tick_elaps(startUpdate) < 250))
         ;
       SET_DIRTY();
 #endif
diff --git a/radio/src/gui/colorlcd/module/multi_rfprotos.cpp b/radio/src/gui/colorlcd/module/multi_rfprotos.cpp
index 2fce5244aa2..888002d1210 100644
--- a/radio/src/gui/colorlcd/module/multi_rfprotos.cpp
+++ b/radio/src/gui/colorlcd/module/multi_rfprotos.cpp
@@ -44,9 +44,9 @@ void RfScanDialog::checkEvents()
 {
   if (!protos->isScanning()) {
     closeDialog();
-  } else if (RTOS_GET_MS() - lastUpdate >= 200) {
+  } else if (lv_tick_elaps(lastUpdate) >= 200) {
     showProgress();
-    lastUpdate = RTOS_GET_MS();
+    lastUpdate = lv_tick_get();
   }
   
   ProgressDialog::checkEvents();
diff --git a/radio/src/gui/colorlcd/radio/radio_ghost_module_config.cpp b/radio/src/gui/colorlcd/radio/radio_ghost_module_config.cpp
index 2f9bff2390c..8ec6250c7bf 100644
--- a/radio/src/gui/colorlcd/radio/radio_ghost_module_config.cpp
+++ b/radio/src/gui/colorlcd/radio/radio_ghost_module_config.cpp
@@ -25,6 +25,7 @@
 #include "edgetx.h"
 #include "telemetry/ghost.h"
 #include "telemetry/ghost_menu.h"
+#include "os/sleep.h"
 
 class GhostModuleConfigWindow : public Window
 {
@@ -166,7 +167,7 @@ void RadioGhostModuleConfig::onLongPressRTN()
   reusableBuffer.ghostMenu.buttonAction = GHST_BTN_NONE;
   reusableBuffer.ghostMenu.menuAction = GHST_MENU_CTRL_CLOSE;
   moduleState[EXTERNAL_MODULE].counter = GHST_MENU_CONTROL;
-  RTOS_WAIT_MS(10);
+  sleep_ms(10);
 #if defined(TRIMS_EMULATE_BUTTONS)
   setHatsAsKeys(false);  // switch trims back to normal
 #endif
@@ -183,7 +184,7 @@ void RadioGhostModuleConfig::checkEvents()
     reusableBuffer.ghostMenu.menuAction = GHST_MENU_CTRL_OPEN;
     moduleState[EXTERNAL_MODULE].counter = GHST_MENU_CONTROL;
   } else if (reusableBuffer.ghostMenu.menuStatus == GHST_MENU_STATUS_CLOSING) {
-    RTOS_WAIT_MS(10);
+    sleep_ms(10);
     deleteLater();
 #if defined(TRIMS_EMULATE_BUTTONS)
     setHatsAsKeys(false);  // switch trims back to normal
diff --git a/radio/src/gui/colorlcd/startup_shutdown.cpp b/radio/src/gui/colorlcd/startup_shutdown.cpp
index 918ad462cf3..c97604c6764 100644
--- a/radio/src/gui/colorlcd/startup_shutdown.cpp
+++ b/radio/src/gui/colorlcd/startup_shutdown.cpp
@@ -22,6 +22,7 @@
 #include "hal/abnormal_reboot.h"
 #include "inactivity_timer.h"
 #include "edgetx.h"
+#include "os/sleep.h"
 #include "stamp.h"
 #include "theme_manager.h"
 
@@ -123,7 +124,7 @@ void waitSplash()
   if (splashStartTime) {
 #if defined(SIMU)
     // Simulator - inputsMoved() returns true immediately without this!
-    RTOS_WAIT_TICKS(30);
+    sleep_ms(30);
 #endif  // defined(SIMU)
 
     splashStartTime += SPLASH_TIMEOUT;
@@ -133,7 +134,7 @@ void waitSplash()
       WDG_RESET();
       checkSpeakerVolume();
       checkBacklight();
-      RTOS_WAIT_TICKS(10);
+      sleep_ms(10);
       auto evt = getEvent();
       if (evt || inactivityCheckInputs()) {
         if (evt) killEvents(evt);
diff --git a/radio/src/gui/common/stdlcd/radio_ghost_menu.cpp b/radio/src/gui/common/stdlcd/radio_ghost_menu.cpp
index 8742214ab13..a0e1e816e76 100644
--- a/radio/src/gui/common/stdlcd/radio_ghost_menu.cpp
+++ b/radio/src/gui/common/stdlcd/radio_ghost_menu.cpp
@@ -20,6 +20,7 @@
  */
 
 #include "edgetx.h"
+#include "os/sleep.h"
 
 #if defined(GHOST) && defined(HARDWARE_EXTERNAL_MODULE)
 
@@ -84,7 +85,7 @@ void menuGhostModuleConfig(event_t event)
       reusableBuffer.ghostMenu.buttonAction = GHST_BTN_NONE;
       reusableBuffer.ghostMenu.menuAction = GHST_MENU_CTRL_CLOSE;
       moduleState[EXTERNAL_MODULE].counter = GHST_MENU_CONTROL;
-      RTOS_WAIT_MS(10);
+      sleep_ms(10);
       popMenu();
       break;
   }
diff --git a/radio/src/gui/common/stdlcd/radio_power_meter.cpp b/radio/src/gui/common/stdlcd/radio_power_meter.cpp
index 05f2e1eccad..c7d6978d5eb 100644
--- a/radio/src/gui/common/stdlcd/radio_power_meter.cpp
+++ b/radio/src/gui/common/stdlcd/radio_power_meter.cpp
@@ -20,6 +20,7 @@
  */
 
 #include "edgetx.h"
+#include "os/sleep.h"
 #include "timers_driver.h"
 
 extern uint8_t g_moduleIdx;
@@ -52,7 +53,7 @@ void menuRadioPowerMeter(event_t event)
     moduleState[g_moduleIdx].readModuleInformation(&reusableBuffer.moduleSetup.pxx2.moduleInformation, PXX2_HW_INFO_TX_ID, PXX2_HW_INFO_TX_ID);
     /* wait 1s to resume normal operation before leaving */
     watchdogSuspend(500 /*5s*/);
-    RTOS_WAIT_MS(1000);
+    sleep_ms(1000);
     return;
   }
 
diff --git a/radio/src/gui/common/stdlcd/radio_spectrum_analyser.cpp b/radio/src/gui/common/stdlcd/radio_spectrum_analyser.cpp
index cea18b8b291..1dd5921f014 100644
--- a/radio/src/gui/common/stdlcd/radio_spectrum_analyser.cpp
+++ b/radio/src/gui/common/stdlcd/radio_spectrum_analyser.cpp
@@ -20,6 +20,7 @@
  */
 
 #include "edgetx.h"
+#include "os/sleep.h"
 #include "timers_driver.h"
 
 extern uint8_t g_moduleIdx;
@@ -49,7 +50,7 @@ void menuRadioSpectrumAnalyser(event_t event)
 #endif
     /* wait 1s to resume normal operation before leaving */
     watchdogSuspend(500 /*5s*/);
-    RTOS_WAIT_MS(1000);
+    sleep_ms(1000);
     return;
   }
 
diff --git a/radio/src/gui/common/stdlcd/splash.cpp b/radio/src/gui/common/stdlcd/splash.cpp
index 0bf96ddc3ba..d52a116dead 100644
--- a/radio/src/gui/common/stdlcd/splash.cpp
+++ b/radio/src/gui/common/stdlcd/splash.cpp
@@ -21,6 +21,7 @@
 
 #include "edgetx.h"
 #include "inactivity_timer.h"
+#include "os/sleep.h"
 
 static bool splashStarted = false;
 
@@ -53,7 +54,7 @@ void waitSplash()
     tmr10ms_t tgtime = get_tmr10ms() + SPLASH_TIMEOUT;
 
     while (tgtime > get_tmr10ms()) {
-      RTOS_WAIT_TICKS(1);
+      sleep_ms(1);
 
       getADC();
 
diff --git a/radio/src/gui/gui_common.cpp b/radio/src/gui/gui_common.cpp
index aa597920a6d..39635b08fb9 100644
--- a/radio/src/gui/gui_common.cpp
+++ b/radio/src/gui/gui_common.cpp
@@ -27,6 +27,7 @@
 #include "edgetx.h"
 #include "switches.h"
 #include "mixes.h"
+#include "os/sleep.h"
 
 #undef CPN
 #include "MultiSubtypeDefs.h"
@@ -756,7 +757,7 @@ static void runAntennaSelectionMenu()
     WDG_RESET();
     MainWindow::instance()->run();
     LvglWrapper::runNested();
-    RTOS_WAIT_MS(20);
+    sleep_ms(20);
   }
 }
 #else
@@ -1229,7 +1230,7 @@ bool confirmModelChange()
   if (TELEMETRY_STREAMING()) {
     RAISE_ALERT(STR_MODEL, STR_MODEL_STILL_POWERED, STR_PRESS_ENTER_TO_CONFIRM, AU_MODEL_STILL_POWERED);
     while (TELEMETRY_STREAMING()) {
-      RTOS_WAIT_MS(20);
+      sleep_ms(20);
       if (readKeys() == (1 << KEY_ENTER)) {
         killEvents(KEY_ENTER);
         return true;
diff --git a/radio/src/hal/fatfs_diskio.cpp b/radio/src/hal/fatfs_diskio.cpp
index e5b62fd456b..39789489336 100644
--- a/radio/src/hal/fatfs_diskio.cpp
+++ b/radio/src/hal/fatfs_diskio.cpp
@@ -23,7 +23,7 @@
 #include "FatFs/diskio.h"
 
 #if FF_FS_REENTRANT != 0
-#include "rtos.h"
+#include "os/task.h"
 #endif
 
 struct fatfs_drive_t {
@@ -31,7 +31,7 @@ struct fatfs_drive_t {
   uint8_t                lun;
   bool                   initialized;
 #if FF_FS_REENTRANT != 0
-  RTOS_MUTEX_HANDLE      mutex;
+  mutex_handle_t         mutex;
 #endif
 };
 
@@ -52,7 +52,7 @@ int fatfsRegisterDriver(const diskio_driver_t* drv, uint8_t lun)
 
 #if FF_FS_REENTRANT != 0
   // init IO mutex only once
-  RTOS_CREATE_MUTEX(drive.mutex);
+  mutex_create(&drive.mutex);
 #endif
 
   return 1;
@@ -100,10 +100,10 @@ int ff_mutex_create(int vol)
 
 int ff_mutex_take(int vol)
 {
-  return RTOS_LOCK_MUTEX(_fatfs_drives[vol].mutex);
+  return mutex_lock(&_fatfs_drives[vol].mutex);
 }
 
-void ff_mutex_give(int vol) { RTOS_UNLOCK_MUTEX(_fatfs_drives[vol].mutex); }
+void ff_mutex_give(int vol) { mutex_unlock(&_fatfs_drives[vol].mutex); }
 
 void ff_mutex_delete(int vol) { }
 
diff --git a/radio/src/io/bootloader_flash.cpp b/radio/src/io/bootloader_flash.cpp
index b92e4a38889..37603c1b2a3 100644
--- a/radio/src/io/bootloader_flash.cpp
+++ b/radio/src/io/bootloader_flash.cpp
@@ -27,6 +27,7 @@
 #include "flash_driver.h"
 
 #include "hal/watchdog_driver.h"
+#include "os/sleep.h"
 
 #if defined(LIBOPENUI)
   #include "libopenui.h"
@@ -104,9 +105,7 @@ void BootloaderFirmwareUpdate::flashFirmware(const char * filename, ProgressHand
     if (f_eof(&file)) break;
 
 #if defined(SIMU)
-    // add an artificial delay and check for simu quit
-    if (SIMU_SLEEP_OR_EXIT_MS(30))
-      break;
+    sleep_ms(30);
 #endif
   }
 
diff --git a/radio/src/io/frsky_firmware_update.cpp b/radio/src/io/frsky_firmware_update.cpp
index 9febcbfae5f..6a64873ecf8 100644
--- a/radio/src/io/frsky_firmware_update.cpp
+++ b/radio/src/io/frsky_firmware_update.cpp
@@ -23,6 +23,7 @@
 #include "edgetx.h"
 #include "frsky_firmware_update.h"
 #include "debug.h"
+#include "os/sleep.h"
 #include "timers_driver.h"
 #include "tasks/mixer_task.h"
 
@@ -118,11 +119,9 @@ bool FrskyDeviceFirmwareUpdate::readBuffer(uint8_t * buffer, uint8_t count, uint
   while (index < count && elapsed < timeout) {
     if (uart_drv->getByte(uart_ctx, &(buffer[index]))) {
       ++index;
-    }
-    else {
-      RTOS_WAIT_MS(1);
-      if (++elapsed == timeout)
-        return false;
+    } else {
+      sleep_ms(1);
+      if (++elapsed == timeout) return false;
     }
   }
 
@@ -131,7 +130,7 @@ bool FrskyDeviceFirmwareUpdate::readBuffer(uint8_t * buffer, uint8_t count, uint
 
 const uint8_t * FrskyDeviceFirmwareUpdate::readFrame(uint32_t timeout)
 {
-  RTOS_WAIT_MS(1);
+  sleep_ms(1);
 
   uint8_t len = 0;
   bool bytestuff = false;
@@ -142,7 +141,7 @@ const uint8_t * FrskyDeviceFirmwareUpdate::readFrame(uint32_t timeout)
     uint8_t byte = 0;
 
     while (uart_drv->getByte(uart_ctx, &byte) == 0) {
-      RTOS_WAIT_MS(1);
+      sleep_ms(1);
       if (elapsed++ >= timeout) {
         TRACE("timeout in frame (len=%d)",len);
         return nullptr;
@@ -178,7 +177,7 @@ bool FrskyDeviceFirmwareUpdate::waitState(State newState, uint32_t timeout)
   static uint8_t pass = 0;
   if (++pass == 10) {
     pass = 0;
-    RTOS_WAIT_MS(1);
+    sleep_ms(1);
   }
   return true;
 #else
@@ -226,7 +225,7 @@ const char * FrskyDeviceFirmwareUpdate::sendPowerOn()
 {
   state = SPORT_POWERUP_REQ;
 
-  RTOS_WAIT_MS(50);
+  sleep_ms(50);
   uart_drv->clearRxBuffer(uart_ctx);
 
   for (int i=0; i<10; i++) {
@@ -242,7 +241,7 @@ const char * FrskyDeviceFirmwareUpdate::sendPowerOn()
 
 const char * FrskyDeviceFirmwareUpdate::sendReqVersion()
 {
-  RTOS_WAIT_MS(20);
+  sleep_ms(20);
   uart_drv->clearRxBuffer(uart_ctx);
 
   state = SPORT_VERSION_REQ;
@@ -354,7 +353,7 @@ const char *FrskyDeviceFirmwareUpdate::doFlashFirmware(
   if (set_pwr) set_pwr(true);
 
   // wait a bit for PWR to settle
-  RTOS_WAIT_MS(1);
+  sleep_ms(1);
 
   // Special update method for X12S / X10 iXJT
   if (module == INTERNAL_MODULE && port == ETX_MOD_PORT_UART && set_bootcmd != nullptr) {
@@ -408,7 +407,7 @@ const char *FrskyDeviceFirmwareUpdate::uploadFileToHorusXJT(
 
     if (count == 0) {
       uart_drv->sendByte(uart_ctx, 0xA1);
-      RTOS_WAIT_MS(50);
+      sleep_ms(50);
       return nullptr;
     }
 
@@ -453,7 +452,7 @@ const char *FrskyDeviceFirmwareUpdate::uploadFileNormal(
   if (result)
     return result;
 
-  RTOS_WAIT_MS(200);
+  sleep_ms(200);
   uart_drv->clearRxBuffer(uart_ctx);
 
   state = SPORT_DATA_TRANSFER;
@@ -519,7 +518,7 @@ const char *FrskyDeviceFirmwareUpdate::flashFirmware(
 
   /* wait 2s off */
   watchdogSuspend(1000 /*10s*/);
-  RTOS_WAIT_MS(2000);
+  sleep_ms(2000);
 
   const char * result = doFlashFirmware(filename, progressHandler);
 
diff --git a/radio/src/io/multi_firmware_update.cpp b/radio/src/io/multi_firmware_update.cpp
index 0a9bec47d78..cb13f3bdb26 100644
--- a/radio/src/io/multi_firmware_update.cpp
+++ b/radio/src/io/multi_firmware_update.cpp
@@ -19,6 +19,7 @@
  * GNU General Public License for more details.
  */
 
+#include "os/sleep.h"
 #if !defined(DISABLE_MULTI_UPDATE)
 
 #include "hal.h"
@@ -32,6 +33,7 @@
 
 #include "timers_driver.h"
 #include "hal/watchdog_driver.h"
+#include "os/time.h"
 
 #include <memory>
 
@@ -157,9 +159,9 @@ void MultiFirmwareUpdateDriver::deinit()
 
 bool MultiFirmwareUpdateDriver::getRxByte(uint8_t & byte) const
 {
-  uint32_t time = RTOS_GET_MS();
+  uint32_t time = time_get_ms();
   
-  while ((RTOS_GET_MS() - time) < 100) {              // 100ms
+  while ((time_get_ms() - time) < 100) {              // 100ms
     if (getByte(byte)) {
 #if defined(DEBUG_EXT_MODULE_FLASH)
       TRACE("[RX] 0x%X", byte);
@@ -220,7 +222,7 @@ const char * MultiFirmwareUpdateDriver::waitForInitialSync()
   // avoids sending STK_READ_SIGN with STK_OK
   // in case the receiver is too slow changing
   // to RX mode (half-duplex).
-  RTOS_WAIT_TICKS(1);
+  sleep_ms(1);
 
   return nullptr;
 }
@@ -258,7 +260,7 @@ const char * MultiFirmwareUpdateDriver::loadAddress(uint32_t offset) const
 
   // avoids sending next page back-to-back with STK_OK
   // in case the receiver is to slow changing to RX mode (half-duplex).
-  RTOS_WAIT_TICKS(1);
+  sleep_ms(1);
 
   return nullptr;
 }
@@ -310,8 +312,7 @@ const char* MultiFirmwareUpdateDriver::flashFirmware(
 #if defined(SIMU)
   for (uint16_t i = 0; i < 100; i++) {
     progressHandler(label, STR_WRITING, i, 100);
-    if (SIMU_SLEEP_OR_EXIT_MS(30))
-      break;
+    sleep_ms(30);
   }
   return nullptr;
 #endif
@@ -321,7 +322,7 @@ const char* MultiFirmwareUpdateDriver::flashFirmware(
 
   /* wait 500ms for power on */
   watchdogSuspend(500 /*5s*/);
-  RTOS_WAIT_MS(500);
+  sleep_ms(500);
 
   result = waitForInitialSync();
   if (result) {
@@ -553,7 +554,7 @@ bool MultiDeviceFirmwareUpdate::flashFirmware(const char * filename, ProgressHan
 
   /* wait 2s off */
   watchdogSuspend(500 /*5s*/);
-  RTOS_WAIT_MS(3000);
+  sleep_ms(3000);
 
   MultiFirmwareUpdateDriver driver(module, type);
   const char * result = driver.flashFirmware(&file, getBasename(filename), progressHandler);
diff --git a/radio/src/io/multi_protolist.cpp b/radio/src/io/multi_protolist.cpp
index bd566e80d31..dac982da94d 100644
--- a/radio/src/io/multi_protolist.cpp
+++ b/radio/src/io/multi_protolist.cpp
@@ -29,30 +29,20 @@
 #include "gui_common.h"
 
 #include "edgetx.h" // reusableBuffer
+#include "os/time.h"
 
 #include <algorithm>
 
-#if !defined(SIMU)
+static timer_handle_t _protoScanTimers[NUM_MODULES] = {TIMER_INITIALIZER};
 
-#include <FreeRTOS/include/FreeRTOS.h>
-#include <FreeRTOS/include/timers.h>
-
-struct ProtoScanTimer {
-  TimerHandle_t timer = nullptr;
-  StaticTimer_t timerBuffer;
-};
-
-static ProtoScanTimer _protoScanTimers[NUM_MODULES];
-
-void MultiRfProtocols::timerCb(TimerHandle_t xTimer)
+void MultiRfProtocols::timerCb(timer_handle_t* h)
 {
-  uint8_t moduleIdx = (uint8_t)(uintptr_t)pvTimerGetTimerID(xTimer);
+  uint8_t moduleIdx = (uint8_t)(h - _protoScanTimers);
   auto instance = MultiRfProtocols::instance(moduleIdx);
   if (instance->scanState == ScanBegin || instance->scanState == Scanning) {
     instance->fillBuiltinProtos();
   }
 }
-#endif
 
 MultiRfProtocols* MultiRfProtocols::_instance[MAX_MODULES] = {};
 
@@ -201,7 +191,7 @@ float MultiRfProtocols::getProgress() const
   
   if (scanState == ScanStop)  return 0.0;
   if (scanState == ScanBegin) {
-    float t = (float)(RTOS_GET_MS() - scanStart) / (float)MULTI_PROTOLIST_START_TIMEOUT;
+    float t = (float)(time_get_ms() - scanStart) / (float)MULTI_PROTOLIST_START_TIMEOUT;
     return t * WAIT_TIME_RATIO;
   }
 
@@ -225,29 +215,17 @@ bool MultiRfProtocols::triggerScan()
     scanState = ScanBegin;
     currentProto = MULTI_INVALID_PROTO;
     moduleState[moduleIdx].mode = MODULE_MODE_GET_HARDWARE_INFO;
-    scanStart = lastScan = RTOS_GET_MS();
+    scanStart = lastScan = time_get_ms();
 
-#if !defined(SIMU)
     auto scanTimer = &_protoScanTimers[moduleIdx];
-    if (!scanTimer->timer) {
-      scanTimer->timer = xTimerCreateStatic(
-          "MPM", MULTI_PROTOLIST_START_TIMEOUT / RTOS_MS_PER_TICK, pdTRUE,
-          (void*)moduleIdx, MultiRfProtocols::timerCb, &scanTimer->timerBuffer);
+    if (!timer_is_created(scanTimer)) {
+      timer_create(scanTimer, MultiRfProtocols::timerCb, "mpm",
+                   MULTI_PROTOLIST_START_TIMEOUT, false);
+      timer_start(scanTimer);
     } else {
-      if (xTimerChangePeriod(scanTimer->timer,
-          MULTI_PROTOLIST_START_TIMEOUT / RTOS_MS_PER_TICK,
-          0) != pdPASS) {
-          /* The timer period could not be reset. */
-      }
+      timer_set_period(scanTimer, MULTI_PROTOLIST_START_TIMEOUT);
     }
 
-    if (scanTimer->timer) {
-      if( xTimerStart( scanTimer->timer, 0 ) != pdPASS ) {
-        /* The timer could not be set into the Active state. */
-      }
-    }
-#endif
-    
     return true;
   }
 
@@ -291,32 +269,18 @@ bool MultiRfProtocols::scanReply(const uint8_t* packet, uint8_t len)
           }
 
           currentProto++;
-          lastScan = RTOS_GET_MS();
+          lastScan = time_get_ms();
 
-#if !defined(SIMU)
           auto scanTimer = &_protoScanTimers[moduleIdx];
-          if (scanTimer->timer) {
-            if (xTimerChangePeriod(scanTimer->timer,
-                                   MULTI_PROTOLIST_TIMEOUT / RTOS_MS_PER_TICK,
-                                   0) != pdPASS) {
-              /* The timer period could not be reset. */
-            }
-          }
-#endif
+          timer_set_period(scanTimer, MULTI_PROTOLIST_TIMEOUT);
+
           return true;
 
         } else {
           scanState = ScanEnd;
           setModuleMode(moduleIdx, MODULE_MODE_NORMAL);
-
-#if !defined(SIMU)
           auto scanTimer = &_protoScanTimers[moduleIdx];
-          if (scanTimer->timer) {
-            if (xTimerStop(scanTimer->timer, 0) != pdPASS) {
-              /* The timer period could not be stopped. */
-            }
-          }
-#endif
+          timer_stop(scanTimer);
           break;
         }
       } else {
@@ -328,7 +292,7 @@ bool MultiRfProtocols::scanReply(const uint8_t* packet, uint8_t len)
           timeout = MULTI_PROTOLIST_START_TIMEOUT;
         }
 
-        if (RTOS_GET_MS() - lastScan >= timeout) {
+        if (time_get_ms() - lastScan >= timeout) {
           TRACE("proto scan timeout!");
           scanState = ScanInvalid;
         }
diff --git a/radio/src/io/multi_protolist.h b/radio/src/io/multi_protolist.h
index a8f56d1b34c..dfe1546fd89 100644
--- a/radio/src/io/multi_protolist.h
+++ b/radio/src/io/multi_protolist.h
@@ -22,17 +22,13 @@
 #include "dataconstants.h"
 #include "edgetx_types.h"
 
+#include "os/timer.h"
+
 #include <functional>
 #include <string>
 #include <vector>
 #include <map>
 
-#if !defined(SIMU)
-// Forward declare FreeRTOS timer
-struct tmrTimerControl;
-typedef struct tmrTimerControl * TimerHandle_t;
-#endif
-
 class MultiRfProtocols
 {
   static MultiRfProtocols* _instance[NUM_MODULES];
@@ -51,9 +47,7 @@ class MultiRfProtocols
   MultiRfProtocols(unsigned int moduleIdx);
   void fillBuiltinProtos();
 
-#if !defined(SIMU)
-  static void timerCb(TimerHandle_t xTimer);
-#endif
+  static void timerCb(timer_handle_t* h);
   
  public:
 
diff --git a/radio/src/logs.cpp b/radio/src/logs.cpp
index 3fd9e9ca978..0d2bc1916b5 100644
--- a/radio/src/logs.cpp
+++ b/radio/src/logs.cpp
@@ -28,6 +28,9 @@
 #include "hal/switch_driver.h"
 #include "hal/usb_driver.h"
 
+#include "os/timer.h"
+#include "tasks/mixer_task.h"
+
 #if defined(LIBOPENUI)
   #include "libopenui.h"
 #endif
@@ -36,18 +39,11 @@ FIL g_oLogFile __DMA;
 uint8_t logDelay100ms;
 static tmr10ms_t lastLogTime = 0;
 
-#if !defined(SIMU)
-#include <FreeRTOS/include/FreeRTOS.h>
-#include <FreeRTOS/include/timers.h>
-
-#include "tasks/mixer_task.h"
+static timer_handle_t loggingTimer = TIMER_INITIALIZER;
 
-static TimerHandle_t loggingTimer = nullptr;
-static StaticTimer_t loggingTimerBuffer;
-
-static void loggingTimerCb(TimerHandle_t xTimer)
+static void loggingTimerCb(timer_handle_t* timer)
 {
-  (void)xTimer;
+  (void)timer;
   if (mixerTaskRunning()) {
     DEBUG_TIMER_START(debugTimerLoggingWakeup);
     logsWrite();
@@ -55,51 +51,39 @@ static void loggingTimerCb(TimerHandle_t xTimer)
   }
 }
 
-void loggingTimerStart()
+void loggingTimerStart(uint32_t period)
 {
-  if (!loggingTimer) {
-    loggingTimer =
-        xTimerCreateStatic("Logging", logDelay100ms*100 / RTOS_MS_PER_TICK, pdTRUE, (void*)0,
-                           loggingTimerCb, &loggingTimerBuffer);
+  if (!timer_is_created(&loggingTimer)) {
+    timer_create(&loggingTimer, loggingTimerCb, "logs", period, true);
   }
 
-  if (loggingTimer) {
-    if( xTimerStart( loggingTimer, 0 ) != pdPASS ) {
-      /* The timer could not be set into the Active state. */
-    }
-  }
+  timer_start(&loggingTimer);
 }
 
-void loggingTimerStop()
+void loggingTimerStop() { timer_stop(&loggingTimer); }
+
+bool loggingTimerIsRunning()
 {
-  if (loggingTimer) {
-    if( xTimerStop( loggingTimer, 120 / RTOS_MS_PER_TICK ) != pdPASS ) {
-      /* The timer could not be stopped. */
-    }
-    loggingTimer = nullptr;
-  }
+  return timer_is_active(&loggingTimer);
 }
 
-void initLoggingTimer() {                                       // called cyclically by main.cpp:perMain()
+void initLoggingTimer()
+{  // called cyclically by main.cpp:perMain()
   static uint8_t logDelay100msOld = 0;
 
-  if(loggingTimer == nullptr) {                                 // log Timer not running
+  if(!timer_is_active(&loggingTimer)) {                         // log Timer not running
     if(isFunctionActive(FUNCTION_LOGS) && logDelay100ms > 0) {  // if SF Logging is active and log rate is valid
-      loggingTimerStart();                                      // start log timer
+      loggingTimerStart(logDelay100ms * 100);                   // start log timer
     }  
   } else {                                                      // log timer is already running
     if(logDelay100msOld != logDelay100ms) {                     // if log rate was changed
       logDelay100msOld = logDelay100ms;                         // memorize new log rate
-
       if(logDelay100ms > 0) {
-        if(xTimerChangePeriod( loggingTimer, logDelay100ms*100, 0 ) != pdPASS ) {  // and restart timer with new log rate
-          /* The timer period could not be changed */
-        }
+        timer_set_period(&loggingTimer, logDelay100ms * 100);
       }
     }
   }
 }
-#endif
 
 void writeHeader();
 
diff --git a/radio/src/lua/lua_widget.cpp b/radio/src/lua/lua_widget.cpp
index e1ee83e81cb..08667943500 100644
--- a/radio/src/lua/lua_widget.cpp
+++ b/radio/src/lua/lua_widget.cpp
@@ -28,6 +28,7 @@
 
 #include "touch.h"
 #include "view_main.h"
+#include "os/time.h"
 
 #define MAX_INSTRUCTIONS (20000 / 100)
 
@@ -117,11 +118,11 @@ void LuaEventHandler::event_cb(lv_event_t* e)
       _startX = rel_pos.x;
       _startY = rel_pos.y;
 
-      downTime = RTOS_GET_MS();
+      downTime = time_get_ms();
     }
   } else if (code == LV_EVENT_RELEASED) {
     // tap count handling
-    uint32_t now = RTOS_GET_MS();
+    uint32_t now = time_get_ms();
     if (now - downTime <= LUA_TAP_TIME) {
       if (now - tapTime > LUA_TAP_TIME) {
         tapCount = 1;
diff --git a/radio/src/main.cpp b/radio/src/main.cpp
index cbcc6fb2ece..496129122a9 100644
--- a/radio/src/main.cpp
+++ b/radio/src/main.cpp
@@ -465,9 +465,8 @@ void guiMain(event_t evt)
 }
 #endif
 
-#if !defined(SIMU)
+// from logs.cpp
 void initLoggingTimer();
-#endif
 
 void perMain()
 {
@@ -477,12 +476,7 @@ void perMain()
 
   if (!usbPlugged() || (getSelectedUsbMode() == USB_UNSELECTED_MODE)) {
     checkStorageUpdate();
-
-#if !defined(SIMU)       // use FreeRTOS software timer if radio firmware
     initLoggingTimer();  // initialize software timer for logging
-#else
-    logsWrite();  // call logsWrite the old way for simu
-#endif
   }
 
   handleUsbConnection();
diff --git a/radio/src/mixer_scheduler.cpp b/radio/src/mixer_scheduler.cpp
index 1fcca7ce339..b150e5f0a43 100644
--- a/radio/src/mixer_scheduler.cpp
+++ b/radio/src/mixer_scheduler.cpp
@@ -19,11 +19,13 @@
  * GNU General Public License for more details.
  */
 
-#include "edgetx.h"
 #include "mixer_scheduler.h"
 #include "tasks/mixer_task.h"
 #include "hal/usb_driver.h"
 
+#include "dataconstants.h"
+#include <string.h>
+
 bool mixerSchedulerWaitForTrigger(uint8_t timeoutMs)
 {
 #if !defined(SIMU)
@@ -111,10 +113,10 @@ void mixerSchedulerISRTrigger()
 
   /* At this point xTaskToNotify should not be NULL as
      a transmission was in progress. */
-  configASSERT( mixerTaskId.rtos_handle != NULL );
+  configASSERT( mixerTaskId._rtos_handle != NULL );
 
   /* Notify the task that the transmission is complete. */
-  vTaskNotifyGiveFromISR( mixerTaskId.rtos_handle,
+  vTaskNotifyGiveFromISR( mixerTaskId._rtos_handle,
                           &xHigherPriorityTaskWoken );
 
   /* If xHigherPriorityTaskWoken is now set to pdTRUE then a
diff --git a/radio/src/os/async.h b/radio/src/os/async.h
new file mode 100644
index 00000000000..bf3cfbafa24
--- /dev/null
+++ b/radio/src/os/async.h
@@ -0,0 +1,36 @@
+/*
+ * Copyright (C) EdgeTX
+ *
+ * Based on code named
+ *   opentx - https://github.com/opentx/opentx
+ *   th9x - http://code.google.com/p/th9x
+ *   er9x - http://code.google.com/p/er9x
+ *   gruvin9x - http://code.google.com/p/gruvin9x
+ *
+ * License GPLv2: http://www.gnu.org/licenses/gpl-2.0.html
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ */
+
+#pragma once
+
+#include <stdint.h>
+#include <stdbool.h>
+
+typedef void (*async_func_t)(void* param1, uint32_t param2);
+
+// schedule a function call for later
+// return true if the async call could be stacked, false otherwise
+bool async_call(async_func_t func, volatile bool* excl_flag, void* param1,
+                uint32_t param2);
+
+// schedule a function call for later (interrupt handler)
+bool async_call_isr(async_func_t func, volatile bool* excl_flag, void* param1,
+                    uint32_t param2);
diff --git a/radio/src/os/async_freertos.cpp b/radio/src/os/async_freertos.cpp
new file mode 100644
index 00000000000..61d99468a90
--- /dev/null
+++ b/radio/src/os/async_freertos.cpp
@@ -0,0 +1,68 @@
+/*
+ * Copyright (C) EdgeTX
+ *
+ * Based on code named
+ *   opentx - https://github.com/opentx/opentx
+ *   th9x - http://code.google.com/p/th9x
+ *   er9x - http://code.google.com/p/er9x
+ *   gruvin9x - http://code.google.com/p/gruvin9x
+ *
+ * License GPLv2: http://www.gnu.org/licenses/gpl-2.0.html
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ */
+
+#include "async.h"
+
+#include <FreeRTOS/include/FreeRTOS.h>
+#include <FreeRTOS/include/timers.h>
+
+bool async_call(async_func_t func, volatile bool* excl_flag, void* param1,
+                uint32_t param2)
+{
+  if (xTaskGetSchedulerState() != taskSCHEDULER_NOT_STARTED) {
+
+    // check exclusive flag first
+    if (excl_flag && *excl_flag) return false;
+
+    BaseType_t xReturn = xTimerPendFunctionCall(func, param1, param2, 0);
+
+    // update exclusive flag if provided
+    if (excl_flag && (xReturn == pdPASS)) *excl_flag = true;
+
+    return xReturn == pdPASS;
+  }
+
+  func(param1, param2);
+  return true;
+}
+
+bool async_call_isr(async_func_t func, volatile bool* excl_flag, void* param1,
+                    uint32_t param2)
+{
+  BaseType_t xHigherPriorityTaskWoken = pdFALSE;
+  if (xTaskGetSchedulerState() != taskSCHEDULER_NOT_STARTED) {
+
+    // check exclusive flag first
+    if (excl_flag && *excl_flag) return false;
+
+    BaseType_t xReturn = xTimerPendFunctionCallFromISR(
+        func, param1, param2, &xHigherPriorityTaskWoken);
+
+    // update exclusive flag if provided
+    if (excl_flag && (xReturn == pdPASS)) *excl_flag = true;
+
+    portYIELD_FROM_ISR(xHigherPriorityTaskWoken);
+    return xReturn == pdPASS;
+  }
+
+  func(param1, param2);
+  return true;
+}
diff --git a/radio/src/os/async_native.cpp b/radio/src/os/async_native.cpp
new file mode 100644
index 00000000000..140dba1248f
--- /dev/null
+++ b/radio/src/os/async_native.cpp
@@ -0,0 +1,38 @@
+/*
+ * Copyright (C) EdgeTX
+ *
+ * Based on code named
+ *   opentx - https://github.com/opentx/opentx
+ *   th9x - http://code.google.com/p/th9x
+ *   er9x - http://code.google.com/p/er9x
+ *   gruvin9x - http://code.google.com/p/gruvin9x
+ *
+ * License GPLv2: http://www.gnu.org/licenses/gpl-2.0.html
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ */
+
+#include "async.h"
+#include "timer_pthread_impl.h"
+
+bool async_call(async_func_t func, volatile bool* excl_flag, void* param1,
+                uint32_t param2)
+{
+  if (excl_flag && *excl_flag) return false;
+  timer_queue::instance().pend_function(func, param1, param2);
+  if (excl_flag) *excl_flag = true;
+  return true;
+}
+
+bool async_call_isr(async_func_t func, volatile bool* excl_flag, void* param1,
+                    uint32_t param2)
+{
+  return async_call(func, excl_flag, param1, param2);
+}
diff --git a/radio/src/os/sleep.h b/radio/src/os/sleep.h
new file mode 100644
index 00000000000..fee5dff46bd
--- /dev/null
+++ b/radio/src/os/sleep.h
@@ -0,0 +1,27 @@
+/*
+ * Copyright (C) EdgeTX
+ *
+ * Based on code named
+ *   opentx - https://github.com/opentx/opentx
+ *   th9x - http://code.google.com/p/th9x
+ *   er9x - http://code.google.com/p/er9x
+ *   gruvin9x - http://code.google.com/p/gruvin9x
+ *
+ * License GPLv2: http://www.gnu.org/licenses/gpl-2.0.html
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ */
+
+#pragma once
+
+#include "time.h"
+
+void sleep_ms(uint32_t ms);
+void sleep_until(time_point_t* tp, uint32_t ts_ms);
diff --git a/radio/src/os/sleep_freertos.cpp b/radio/src/os/sleep_freertos.cpp
new file mode 100644
index 00000000000..492edb99d45
--- /dev/null
+++ b/radio/src/os/sleep_freertos.cpp
@@ -0,0 +1,41 @@
+/*
+ * Copyright (C) EdgeTX
+ *
+ * Based on code named
+ *   opentx - https://github.com/opentx/opentx
+ *   th9x - http://code.google.com/p/th9x
+ *   er9x - http://code.google.com/p/er9x
+ *   gruvin9x - http://code.google.com/p/gruvin9x
+ *
+ * License GPLv2: http://www.gnu.org/licenses/gpl-2.0.html
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ */
+
+#include "sleep.h"
+
+#include <FreeRTOS/include/FreeRTOS.h>
+#include <FreeRTOS/include/task.h>
+    
+void sleep_ms(uint32_t ms)
+{
+  if (!ms) return;
+
+  ms /= portTICK_PERIOD_MS;
+  if (!ms) ms = 1;
+
+  vTaskDelay(ms);
+}
+
+void sleep_until(time_point_t* tp, uint32_t inc)
+{
+  inc /= portTICK_PERIOD_MS;
+  vTaskDelayUntil(tp, inc);
+}
diff --git a/radio/src/os/sleep_native.cpp b/radio/src/os/sleep_native.cpp
new file mode 100644
index 00000000000..2f6849373e8
--- /dev/null
+++ b/radio/src/os/sleep_native.cpp
@@ -0,0 +1,37 @@
+/*
+ * Copyright (C) EdgeTX
+ *
+ * Based on code named
+ *   opentx - https://github.com/opentx/opentx
+ *   th9x - http://code.google.com/p/th9x
+ *   er9x - http://code.google.com/p/er9x
+ *   gruvin9x - http://code.google.com/p/gruvin9x
+ *
+ * License GPLv2: http://www.gnu.org/licenses/gpl-2.0.html
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ */
+
+#include "sleep.h"
+
+#include <thread>
+
+extern uint8_t simuSleep(uint32_t ms);
+
+void sleep_ms(uint32_t ms)
+{
+  simuSleep(ms);
+}
+
+void sleep_until(time_point_t* tp, uint32_t inc)
+{
+  *tp += std::chrono::duration<uint32_t, std::milli>{inc};
+  std::this_thread::sleep_until(*tp);
+}
diff --git a/radio/src/os/sleep_nortos.cpp b/radio/src/os/sleep_nortos.cpp
new file mode 100644
index 00000000000..b317da8c2ba
--- /dev/null
+++ b/radio/src/os/sleep_nortos.cpp
@@ -0,0 +1,41 @@
+/*
+ * Copyright (C) EdgeTX
+ *
+ * Based on code named
+ *   opentx - https://github.com/opentx/opentx
+ *   th9x - http://code.google.com/p/th9x
+ *   er9x - http://code.google.com/p/er9x
+ *   gruvin9x - http://code.google.com/p/gruvin9x
+ *
+ * License GPLv2: http://www.gnu.org/licenses/gpl-2.0.html
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ */
+
+#include "sleep.h"
+
+#include "timers_driver.h"
+    
+void sleep_ms(uint32_t ms)
+{
+  if (!ms) return;
+
+  uint32_t timeout = timersGetMsTick();
+  while (timersGetMsTick() - timeout < ms) {}
+}
+
+void sleep_until(time_point_t* tp, uint32_t inc)
+{
+  uint32_t start = *tp;
+  *tp = start + inc;
+
+  while (timersGetMsTick() - start < inc) {}
+}
+
diff --git a/radio/src/os/task.h b/radio/src/os/task.h
new file mode 100644
index 00000000000..8a48120d647
--- /dev/null
+++ b/radio/src/os/task.h
@@ -0,0 +1,46 @@
+/*
+ * Copyright (C) EdgeTX
+ *
+ * Based on code named
+ *   opentx - https://github.com/opentx/opentx
+ *   th9x - http://code.google.com/p/th9x
+ *   er9x - http://code.google.com/p/er9x
+ *   gruvin9x - http://code.google.com/p/gruvin9x
+ *
+ * License GPLv2: http://www.gnu.org/licenses/gpl-2.0.html
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ */
+
+#pragma once
+
+#include <stdint.h>
+#include <stdbool.h>
+
+// OS specific implementation
+#if defined(POSIX_THREADS)
+  #include "task_pthread.h"
+#elif defined(FREE_RTOS)
+  #include "task_freertos.h"
+#endif
+
+typedef void (*task_func_t)();
+
+void task_create(task_handle_t* h, task_func_t func, const char* name,
+                 void* stack, unsigned stack_size, unsigned priority);
+
+unsigned task_get_stack_usage(task_handle_t* h);
+unsigned task_get_stack_size(task_handle_t* h);
+
+void mutex_create(mutex_handle_t* h);
+bool mutex_lock(mutex_handle_t* h);
+void mutex_unlock(mutex_handle_t* h);
+bool mutex_trylock(mutex_handle_t* h);
+
diff --git a/radio/src/os/task_freertos.cpp b/radio/src/os/task_freertos.cpp
new file mode 100644
index 00000000000..ae60ff40b1e
--- /dev/null
+++ b/radio/src/os/task_freertos.cpp
@@ -0,0 +1,62 @@
+/*
+ * Copyright (C) EdgeTX
+ *
+ * Based on code named
+ *   opentx - https://github.com/opentx/opentx
+ *   th9x - http://code.google.com/p/th9x
+ *   er9x - http://code.google.com/p/er9x
+ *   gruvin9x - http://code.google.com/p/gruvin9x
+ *
+ * License GPLv2: http://www.gnu.org/licenses/gpl-2.0.html
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ */
+
+#include "task.h"
+
+static void _task_stub(void* p)
+{
+  task_func_t func = (task_func_t)p;
+  func();
+}
+
+void task_create(task_handle_t* h, task_func_t func, const char* name,
+                 void* stack, unsigned stack_size, unsigned priority)
+{
+  h->_stack_size = stack_size;
+  h->_rtos_handle =
+      xTaskCreateStatic(_task_stub, name, stack_size, (void*)func, priority,
+                        (StackType_t*)stack, &h->_task_struct);
+}
+
+unsigned task_get_stack_usage(task_handle_t* h)
+{
+  return uxTaskGetStackHighWaterMark(h->_rtos_handle);
+}
+
+unsigned task_get_stack_size(task_handle_t* h)
+{
+  return h->_stack_size * sizeof(StackType_t);
+}
+
+void mutex_create(mutex_handle_t* h)
+{
+  h->_rtos_handle = xSemaphoreCreateMutexStatic(&h->_mutex_struct);
+  mutex_unlock(h);
+}
+
+static inline bool _lock_mutex(mutex_handle_t* h, TickType_t xTickToWait)
+{
+  return xSemaphoreTake(h->_rtos_handle, xTickToWait) == pdTRUE;
+}
+
+bool mutex_lock(mutex_handle_t* h) { return _lock_mutex(h, portMAX_DELAY); }
+bool mutex_trylock(mutex_handle_t* h) { return _lock_mutex(h, (TickType_t)0); }
+void mutex_unlock(mutex_handle_t* h) { xSemaphoreGive(h->_rtos_handle); }
diff --git a/radio/src/os/task_freertos.h b/radio/src/os/task_freertos.h
new file mode 100644
index 00000000000..8e12d51b725
--- /dev/null
+++ b/radio/src/os/task_freertos.h
@@ -0,0 +1,41 @@
+/*
+ * Copyright (C) EdgeTX
+ *
+ * Based on code named
+ *   opentx - https://github.com/opentx/opentx
+ *   th9x - http://code.google.com/p/th9x
+ *   er9x - http://code.google.com/p/er9x
+ *   gruvin9x - http://code.google.com/p/gruvin9x
+ *
+ * License GPLv2: http://www.gnu.org/licenses/gpl-2.0.html
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ */
+
+#pragma once
+
+#include <FreeRTOS/include/FreeRTOS.h>
+#include <FreeRTOS/include/task.h>
+#include <FreeRTOS/include/semphr.h>
+
+#include "definitions.h"
+
+#define TASK_DEFINE_STACK(name, size) StackType_t __ALIGNED(8) name[size] __CCMRAM
+
+struct task_handle_t {
+  TaskHandle_t _rtos_handle;
+  StaticTask_t _task_struct;
+  uint32_t     _stack_size;
+};
+
+struct mutex_handle_t {
+  SemaphoreHandle_t _rtos_handle;
+  StaticSemaphore_t _mutex_struct;
+};
diff --git a/radio/src/os/task_pthread.cpp b/radio/src/os/task_pthread.cpp
new file mode 100644
index 00000000000..d2775bd0136
--- /dev/null
+++ b/radio/src/os/task_pthread.cpp
@@ -0,0 +1,69 @@
+/*
+ * Copyright (C) EdgeTX
+ *
+ * Based on code named
+ *   opentx - https://github.com/opentx/opentx
+ *   th9x - http://code.google.com/p/th9x
+ *   er9x - http://code.google.com/p/er9x
+ *   gruvin9x - http://code.google.com/p/gruvin9x
+ *
+ * License GPLv2: http://www.gnu.org/licenses/gpl-2.0.html
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ */
+
+#include "task.h"
+
+static void* _task_stub(void* p)
+{
+  task_func_t func = (task_func_t)p;
+  func();
+  return nullptr;
+}
+
+void task_create(task_handle_t* h, task_func_t func, const char* name,
+                 void* stack, unsigned stack_size, unsigned priority)
+{
+  h->_stack_size = stack_size;
+  pthread_create(&h->_thread_handle, nullptr, _task_stub, (void*)func);
+}
+
+unsigned task_get_stack_usage(task_handle_t* h)
+{
+  // fake...
+  return 0;
+}
+
+unsigned task_get_stack_size(task_handle_t* h)
+{
+  return h->_stack_size * 4;
+}
+
+void mutex_create(mutex_handle_t* h)
+{
+  *h = PTHREAD_MUTEX_INITIALIZER;
+}
+
+bool mutex_lock(mutex_handle_t* h)
+{
+  return pthread_mutex_lock(h) == 0;
+}
+
+void mutex_unlock(mutex_handle_t* h)
+{
+  pthread_mutex_unlock(h);
+}
+
+bool mutex_trylock(mutex_handle_t* h)
+{
+  return pthread_mutex_trylock(h) == 0;
+}
+
+
diff --git a/radio/src/os/task_pthread.h b/radio/src/os/task_pthread.h
new file mode 100644
index 00000000000..1da334cfb73
--- /dev/null
+++ b/radio/src/os/task_pthread.h
@@ -0,0 +1,36 @@
+/*
+ * Copyright (C) EdgeTX
+ *
+ * Based on code named
+ *   opentx - https://github.com/opentx/opentx
+ *   th9x - http://code.google.com/p/th9x
+ *   er9x - http://code.google.com/p/er9x
+ *   gruvin9x - http://code.google.com/p/gruvin9x
+ *
+ * License GPLv2: http://www.gnu.org/licenses/gpl-2.0.html
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ */
+
+#pragma once
+
+#include <pthread.h>
+#include <semaphore.h>
+
+#include "definitions.h"
+
+#define TASK_DEFINE_STACK(name, size) void* name
+
+struct task_handle_t {
+  pthread_t _thread_handle;
+  uint32_t  _stack_size;
+};
+
+typedef pthread_mutex_t mutex_handle_t;
diff --git a/radio/src/os/time.h b/radio/src/os/time.h
new file mode 100644
index 00000000000..d497c9c293a
--- /dev/null
+++ b/radio/src/os/time.h
@@ -0,0 +1,37 @@
+/*
+ * Copyright (C) EdgeTX
+ *
+ * Based on code named
+ *   opentx - https://github.com/opentx/opentx
+ *   th9x - http://code.google.com/p/th9x
+ *   er9x - http://code.google.com/p/er9x
+ *   gruvin9x - http://code.google.com/p/gruvin9x
+ *
+ * License GPLv2: http://www.gnu.org/licenses/gpl-2.0.html
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ */
+
+#pragma once
+
+#include <stdint.h>
+
+// OS specific implementation
+#if defined(POSIX_THREADS)
+  #include "time_native.h"
+#elif defined(FREE_RTOS)
+  #include "time_freertos.h"
+#else
+  #include "time_nortos.h"
+#endif
+
+uint32_t time_get_ms();
+
+time_point_t time_point_now();
diff --git a/radio/src/os/time_freertos.cpp b/radio/src/os/time_freertos.cpp
new file mode 100644
index 00000000000..140bbb175ba
--- /dev/null
+++ b/radio/src/os/time_freertos.cpp
@@ -0,0 +1,35 @@
+/*
+ * Copyright (C) EdgeTX
+ *
+ * Based on code named
+ *   opentx - https://github.com/opentx/opentx
+ *   th9x - http://code.google.com/p/th9x
+ *   er9x - http://code.google.com/p/er9x
+ *   gruvin9x - http://code.google.com/p/gruvin9x
+ *
+ * License GPLv2: http://www.gnu.org/licenses/gpl-2.0.html
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ */
+
+#include "time.h"
+
+#include <FreeRTOS/include/FreeRTOS.h>
+#include <FreeRTOS/include/task.h>
+
+uint32_t time_get_ms()
+{
+  return xTaskGetTickCount() / portTICK_PERIOD_MS;
+}
+
+time_point_t time_point_now()
+{
+  return xTaskGetTickCount();
+}
diff --git a/radio/src/os/time_freertos.h b/radio/src/os/time_freertos.h
new file mode 100644
index 00000000000..d95d96d8f97
--- /dev/null
+++ b/radio/src/os/time_freertos.h
@@ -0,0 +1,26 @@
+/*
+ * Copyright (C) EdgeTX
+ *
+ * Based on code named
+ *   opentx - https://github.com/opentx/opentx
+ *   th9x - http://code.google.com/p/th9x
+ *   er9x - http://code.google.com/p/er9x
+ *   gruvin9x - http://code.google.com/p/gruvin9x
+ *
+ * License GPLv2: http://www.gnu.org/licenses/gpl-2.0.html
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ */
+
+#pragma once
+
+#include <FreeRTOS/include/FreeRTOS.h>
+
+typedef TickType_t time_point_t;
diff --git a/radio/src/os/time_native.cpp b/radio/src/os/time_native.cpp
new file mode 100644
index 00000000000..59f0ad370f9
--- /dev/null
+++ b/radio/src/os/time_native.cpp
@@ -0,0 +1,36 @@
+/*
+ * Copyright (C) EdgeTX
+ *
+ * Based on code named
+ *   opentx - https://github.com/opentx/opentx
+ *   th9x - http://code.google.com/p/th9x
+ *   er9x - http://code.google.com/p/er9x
+ *   gruvin9x - http://code.google.com/p/gruvin9x
+ *
+ * License GPLv2: http://www.gnu.org/licenses/gpl-2.0.html
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ */
+
+#include "time.h"
+
+#include <chrono>
+
+extern uint64_t simuTimerMicros(void);
+
+uint32_t time_get_ms()
+{
+  return simuTimerMicros() / 1000;
+}
+
+time_point_t time_point_now()
+{
+  return std::chrono::steady_clock::now();
+}
diff --git a/radio/src/os/time_native.h b/radio/src/os/time_native.h
new file mode 100644
index 00000000000..eb8d2a3dcf5
--- /dev/null
+++ b/radio/src/os/time_native.h
@@ -0,0 +1,27 @@
+/*
+ * Copyright (C) EdgeTX
+ *
+ * Based on code named
+ *   opentx - https://github.com/opentx/opentx
+ *   th9x - http://code.google.com/p/th9x
+ *   er9x - http://code.google.com/p/er9x
+ *   gruvin9x - http://code.google.com/p/gruvin9x
+ *
+ * License GPLv2: http://www.gnu.org/licenses/gpl-2.0.html
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ */
+
+#pragma once
+
+#include <chrono>
+
+typedef std::chrono::time_point<std::chrono::steady_clock> time_point_t;
+
diff --git a/radio/src/os/time_nortos.cpp b/radio/src/os/time_nortos.cpp
new file mode 100644
index 00000000000..255e81c3a85
--- /dev/null
+++ b/radio/src/os/time_nortos.cpp
@@ -0,0 +1,35 @@
+/*
+ * Copyright (C) EdgeTX
+ *
+ * Based on code named
+ *   opentx - https://github.com/opentx/opentx
+ *   th9x - http://code.google.com/p/th9x
+ *   er9x - http://code.google.com/p/er9x
+ *   gruvin9x - http://code.google.com/p/gruvin9x
+ *
+ * License GPLv2: http://www.gnu.org/licenses/gpl-2.0.html
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ */
+
+#include "time.h"
+
+#include "timers_driver.h"
+
+uint32_t time_get_ms()
+{
+  return timersGetMsTick();
+}
+
+time_point_t time_point_now()
+{
+  return time_get_ms();
+}
+
diff --git a/radio/src/os/time_nortos.h b/radio/src/os/time_nortos.h
new file mode 100644
index 00000000000..0579aed526c
--- /dev/null
+++ b/radio/src/os/time_nortos.h
@@ -0,0 +1,27 @@
+/*
+ * Copyright (C) EdgeTX
+ *
+ * Based on code named
+ *   opentx - https://github.com/opentx/opentx
+ *   th9x - http://code.google.com/p/th9x
+ *   er9x - http://code.google.com/p/er9x
+ *   gruvin9x - http://code.google.com/p/gruvin9x
+ *
+ * License GPLv2: http://www.gnu.org/licenses/gpl-2.0.html
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ */
+
+#pragma once
+
+#include <stdint.h>
+
+typedef uint32_t time_point_t;
+
diff --git a/radio/src/os/timer.h b/radio/src/os/timer.h
new file mode 100644
index 00000000000..ba56385cb83
--- /dev/null
+++ b/radio/src/os/timer.h
@@ -0,0 +1,45 @@
+/*
+ * Copyright (C) EdgeTX
+ *
+ * Based on code named
+ *   opentx - https://github.com/opentx/opentx
+ *   th9x - http://code.google.com/p/th9x
+ *   er9x - http://code.google.com/p/er9x
+ *   gruvin9x - http://code.google.com/p/gruvin9x
+ *
+ * License GPLv2: http://www.gnu.org/licenses/gpl-2.0.html
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ */
+
+#pragma once
+
+#include <stdint.h>
+#include <stdbool.h>
+
+// OS specific implementation
+#if defined(POSIX_THREADS)
+  #include "timer_pthread.h"
+#elif defined(FREE_RTOS)
+  #include "timer_freertos.h"
+#endif
+
+typedef void (*timer_func_t)(timer_handle_t*);
+
+int timer_create(timer_handle_t* h, timer_func_t func, const char* name,
+                 unsigned period, bool repeat);
+
+bool timer_is_created(timer_handle_t* h);
+bool timer_is_active(timer_handle_t* h);
+
+int timer_start(timer_handle_t* h);
+int timer_stop(timer_handle_t* h);
+
+int timer_set_period(timer_handle_t* h, unsigned period);
diff --git a/radio/src/os/timer_freertos.cpp b/radio/src/os/timer_freertos.cpp
new file mode 100644
index 00000000000..895f23480f0
--- /dev/null
+++ b/radio/src/os/timer_freertos.cpp
@@ -0,0 +1,70 @@
+/*
+ * Copyright (C) EdgeTX
+ *
+ * Based on code named
+ *   opentx - https://github.com/opentx/opentx
+ *   th9x - http://code.google.com/p/th9x
+ *   er9x - http://code.google.com/p/er9x
+ *   gruvin9x - http://code.google.com/p/gruvin9x
+ *
+ * License GPLv2: http://www.gnu.org/licenses/gpl-2.0.html
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ */
+
+#include "timer.h"
+
+static void _timer_cb(TimerHandle_t xTimer)
+{
+  timer_handle_t* h = (timer_handle_t*)pvTimerGetTimerID(xTimer);
+  if (h->_func) h->_func(h);
+}
+
+int timer_create(timer_handle_t* h, timer_func_t func, const char* name,
+                  unsigned period, bool repeat)
+{
+  if (h->_rtos_handle) return -1;
+  h->_rtos_handle = xTimerCreateStatic(name, period / portTICK_PERIOD_MS,
+                                       repeat ? pdTRUE : pdFALSE, (void*)h,
+                                       _timer_cb, &h->_timer_struct);
+  h->_func = func;
+  return 0;
+}
+
+bool timer_is_created(timer_handle_t* h)
+{
+  return h->_rtos_handle != nullptr;  
+}
+
+bool timer_is_active(timer_handle_t* h)
+{
+  return (h->_rtos_handle != nullptr) && (xTimerIsTimerActive(h->_rtos_handle));
+}
+
+int timer_start(timer_handle_t* h)
+{
+  if (!h->_rtos_handle) return -1;
+  return xTimerStart(h->_rtos_handle, 0) == pdPASS ? 0 : -1;
+}
+
+int timer_stop(timer_handle_t* h)
+{
+  if (!h->_rtos_handle) return -1;
+  return xTimerStop(h->_rtos_handle, 0) == pdPASS ? 0 : -1;
+}
+
+int timer_set_period(timer_handle_t* h, unsigned period)
+{
+  if (!h->_rtos_handle) return -1;
+  return xTimerChangePeriod(h->_rtos_handle, period / portTICK_PERIOD_MS, 0) ==
+                 pdPASS
+             ? 0
+             : -1;
+}
diff --git a/radio/src/os/timer_freertos.h b/radio/src/os/timer_freertos.h
new file mode 100644
index 00000000000..4b372f7c811
--- /dev/null
+++ b/radio/src/os/timer_freertos.h
@@ -0,0 +1,35 @@
+/*
+ * Copyright (C) EdgeTX
+ *
+ * Based on code named
+ *   opentx - https://github.com/opentx/opentx
+ *   th9x - http://code.google.com/p/th9x
+ *   er9x - http://code.google.com/p/er9x
+ *   gruvin9x - http://code.google.com/p/gruvin9x
+ *
+ * License GPLv2: http://www.gnu.org/licenses/gpl-2.0.html
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ */
+
+#pragma once
+
+#include <FreeRTOS/include/FreeRTOS.h>
+#include <FreeRTOS/include/timers.h>
+
+struct timer_handle_t;
+
+struct timer_handle_t {
+  TimerHandle_t _rtos_handle;
+  StaticTimer_t _timer_struct;
+  void (*_func)(timer_handle_t*);
+};
+
+#define TIMER_INITIALIZER { ._rtos_handle = nullptr }
diff --git a/radio/src/os/timer_pthread.cpp b/radio/src/os/timer_pthread.cpp
new file mode 100644
index 00000000000..02e3e0d6388
--- /dev/null
+++ b/radio/src/os/timer_pthread.cpp
@@ -0,0 +1,215 @@
+#include "timer.h"
+#include "timer_pthread_impl.h"
+
+#include <algorithm>
+
+bool _timer_cmp(timer_handle_t *lh, timer_handle_t *rh) {
+  return lh->next_trigger < rh->next_trigger;
+}
+
+timer_queue::timer_queue() {}
+
+void timer_queue::update_current_time() {
+  _current_time = std::chrono::steady_clock::now();
+}
+
+void timer_queue::sort_timers() {
+  std::sort(_timers.begin(), _timers.end(), _timer_cmp);
+}
+
+timer_queue& timer_queue::instance()
+{
+  static timer_queue _instance;
+  return _instance;
+}
+
+void timer_queue::start()
+{
+  std::lock_guard<std::mutex> lock(_cmds_mutex);
+  if (!_running) {
+    _running = true;
+    _thread = std::make_unique<std::thread>([&]() { main_loop(); });
+  }
+}
+
+void timer_queue::stop() {
+  bool stopping = false;
+
+  std::unique_lock<std::mutex> lock(_cmds_mutex);
+  std::unique_lock<std::mutex> slock(_stop_mutex);
+
+  if (_running) {
+    stopping = true;
+    _running = false;
+    lock.unlock();
+    _cmds_condition.notify_one();
+    _stop_condition.wait(slock);
+    slock.unlock();
+  }
+  _thread->join();
+}
+
+void timer_queue::create_timer(timer_handle_t *timer, timer_func_t func, const char *name,
+                            unsigned period, bool repeat) {
+  timer->func = func;
+  timer->name = name;
+  timer->period = period;
+  timer->repeat = repeat;
+  timer->next_trigger = time_point_t{};
+}
+
+void timer_queue::send_cmd(timer_req_t&& req)
+{
+  {
+    std::lock_guard lock(_cmds_mutex);
+    _cmds.emplace_back(req);
+  }
+  _cmds_condition.notify_one();
+}
+
+void timer_queue::start_timer(timer_handle_t *timer) {
+  send_cmd(timer_req_t{.cmd = timer_req_t::cmd_start, .timer = timer});
+}
+
+void timer_queue::stop_timer(timer_handle_t *timer) {
+  send_cmd(timer_req_t{.cmd = timer_req_t::cmd_stop, .timer = timer});
+}
+
+void timer_queue::pend_function(timer_async_func_t func, void *param1,
+                                uint32_t param2) {
+  send_cmd(timer_req_t{
+      .cmd = timer_req_t::cmd_pend_func,
+      .func_call = {.func = func, .param1 = param1, .param2 = param2}});
+}
+
+void timer_queue::main_loop() {
+
+  while (true) {
+    {
+      std::unique_lock lock(_cmds_mutex);
+      time_point_t until;
+      
+      update_current_time();
+      process_cmds();
+
+      if (_timers.size() > 0) {
+        timer_handle_t* t = _timers[0];
+        until = t->next_trigger;
+      } else {
+        until = _current_time + std::chrono::milliseconds(1000);
+      }
+
+      std::cv_status result = _cmds_condition.wait_until(lock, until);
+      if (!_running) break;
+    }
+
+    async_calls();
+    trigger_timers();
+  }
+
+  _stop_condition.notify_one();
+}
+
+void timer_queue::process_cmds()
+{
+  while (!_cmds.empty()) {
+    timer_req_t req = _cmds.back();
+    _cmds.pop_back();
+
+    if (req.cmd == timer_req_t::cmd_pend_func) {
+      if (req.func_call.func) {
+        _funcs.emplace_back(std::move(req.func_call));
+      }
+    } else {
+      timer_handle_t *t = req.timer;
+      auto pos = std::find(_timers.begin(), _timers.end(), t);
+      switch (req.cmd) {
+      case timer_req_t::cmd_start:
+        t->next_trigger = _current_time + std::chrono::milliseconds(t->period);
+        t->active = true;
+        if (pos == _timers.end()) {
+          _timers.emplace_back(t);
+        }
+        break;
+
+      case timer_req_t::cmd_stop:
+        if (pos != _timers.end()) {
+          _timers.erase(pos);
+        }
+        break;
+
+      default:
+        break;
+      }
+    }
+  }
+}
+
+void timer_queue::trigger_timers() {
+  int triggered = 0;
+  for (auto t : _timers) {
+    if (t->next_trigger <= _current_time) {
+      if (t->repeat) {
+        t->next_trigger += std::chrono::milliseconds(t->period);
+      } else {
+        t->active = false;
+        stop_timer(t);
+      }
+      t->func(t);
+      triggered++;
+    } else {
+      break;
+    }
+  }
+
+  if (triggered) {
+    sort_timers();
+  }
+}
+
+void timer_queue::async_calls() {
+  for (auto f : _funcs) {
+    f.func(f.param1, f.param2);
+  }
+  _funcs.clear();
+}
+
+int timer_create(timer_handle_t* h, timer_func_t func, const char* name,
+                 unsigned period, bool repeat)
+{
+  if (!h || !func) return -1;
+  timer_queue::create_timer(h, func, name, period, repeat);
+  return 0;
+}
+
+bool timer_is_created(timer_handle_t* h)
+{
+  return h && h->func;
+}
+
+bool timer_is_active(timer_handle_t* h)
+{
+  return h && h->active;
+}
+
+int timer_start(timer_handle_t* h)
+{
+  if (!timer_is_created(h)) return -1;
+  timer_queue::instance().start_timer(h);
+  return 0;
+}
+
+int timer_stop(timer_handle_t* h)
+{
+  if (!timer_is_created(h)) return -1;
+  timer_queue::instance().stop_timer(h);
+  return 0; 
+}
+
+int timer_set_period(timer_handle_t *h, unsigned period)
+{
+  if (!timer_is_created(h)) return -1;
+  h->period = period;
+  timer_queue::instance().start_timer(h);
+  return 0;
+}
diff --git a/radio/src/os/timer_pthread.h b/radio/src/os/timer_pthread.h
new file mode 100644
index 00000000000..f879d1b8045
--- /dev/null
+++ b/radio/src/os/timer_pthread.h
@@ -0,0 +1,45 @@
+/*
+ * Copyright (C) EdgeTX
+ *
+ * Based on code named
+ *   opentx - https://github.com/opentx/opentx
+ *   th9x - http://code.google.com/p/th9x
+ *   er9x - http://code.google.com/p/er9x
+ *   gruvin9x - http://code.google.com/p/gruvin9x
+ *
+ * License GPLv2: http://www.gnu.org/licenses/gpl-2.0.html
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ */
+
+#pragma once
+
+#include "time.h"
+
+#include <atomic>
+
+struct timer_handle_t;
+typedef void (*timer_func_t)(timer_handle_t*);
+typedef void (*timer_async_func_t)(void*, uint32_t);
+
+using time_point = std::chrono::time_point<std::chrono::steady_clock>;
+
+struct timer_handle_t {
+  timer_func_t func;
+  const char*  name;
+  unsigned     period;
+  bool         repeat;
+
+  time_point_t next_trigger;
+  std::atomic_bool active;
+};
+
+#define TIMER_INITIALIZER {}
+
diff --git a/radio/src/os/timer_pthread_impl.h b/radio/src/os/timer_pthread_impl.h
new file mode 100644
index 00000000000..931d3d9eb0c
--- /dev/null
+++ b/radio/src/os/timer_pthread_impl.h
@@ -0,0 +1,74 @@
+#include "timer_pthread.h"
+
+#include <condition_variable>
+#include <deque>
+#include <memory>
+#include <mutex>
+#include <thread>
+#include <vector>
+
+struct timer_async_call_t {
+  timer_async_func_t func;
+  void *param1;
+  uint32_t param2;
+};
+
+struct timer_req_t {
+  enum type {
+    cmd_start,
+    cmd_stop,
+    cmd_pend_func,
+  };
+
+  type cmd;
+
+  union {
+    timer_handle_t *timer;
+    timer_async_call_t func_call;
+  };
+};
+
+class timer_queue {
+
+  std::unique_ptr<std::thread> _thread;
+  bool _running;
+
+  std::deque<timer_req_t> _cmds;
+  std::mutex _cmds_mutex;
+  std::condition_variable _cmds_condition;
+
+  std::mutex _stop_mutex;
+  std::condition_variable _stop_condition;
+
+  std::vector<timer_handle_t*> _timers;
+  std::vector<timer_async_call_t> _funcs;
+
+  time_point_t _current_time;
+  
+  timer_queue();
+
+  void update_current_time();
+  void sort_timers();
+  void main_loop();
+  void trigger_timers();
+  void async_calls();
+  void process_cmds();
+  void send_cmd(timer_req_t&& req);
+
+public:
+  timer_queue(timer_queue const &) = delete;
+  void operator=(timer_queue const &) = delete;
+
+  static timer_queue &instance();
+
+  static void create_timer(timer_handle_t *timer, timer_func_t func, const char *name,
+                           unsigned period, bool repeat);
+
+  void start();
+  void stop();
+
+  void start_timer(timer_handle_t *timer);
+  void stop_timer(timer_handle_t *timer);
+
+  void pend_function(timer_async_func_t func, void* param1, uint32_t param2);
+};
diff --git a/radio/src/pulses/pulses.cpp b/radio/src/pulses/pulses.cpp
index 5ee31deee09..5106c1000b4 100644
--- a/radio/src/pulses/pulses.cpp
+++ b/radio/src/pulses/pulses.cpp
@@ -25,7 +25,9 @@
 #include "mixer_scheduler.h"
 #include "heartbeat_driver.h"
 #include "hal/module_port.h"
+#include "os/sleep.h"
 #include "tasks/mixer_task.h"
+#include "os/async.h"
 
 #include "pulses/pxx2.h"
 #include "pulses/flysky.h"
@@ -106,7 +108,7 @@ void restartModule(uint8_t module)
 
   // wait for the power output to be drained
   pulsesStopModule(module);
-  RTOS_WAIT_MS(200);
+  sleep_ms(200);
 
   mixerTaskStart();
 }
@@ -124,21 +126,21 @@ void pulsesRestartModuleUnsafe(uint8_t module)
   mod_drv->ctx = drv->init(module);
 }
 
-#if !defined(SIMU)
-#include <FreeRTOS/include/FreeRTOS.h>
-#include <FreeRTOS/include/timers.h>
+static volatile bool _module_restart_queued[NUM_MODULES] = {false};
 
 static void _setup_async_module_restart(void* p1, uint32_t p2)
 {
+  uint8_t module = (uint8_t)(uintptr_t)p1;
+  _module_restart_queued[module] = false;
+
   if (!mixerTaskTryLock()) {
     // In case the mixer cannot be locked, try again later
     // and make the same function pending again.
-    PendedFunction_t cb = _setup_async_module_restart;
-    xTimerPendFunctionCall(cb, p1, p2, 0/* do not wait */);
+    async_call(_setup_async_module_restart, &_module_restart_queued[module], p1,
+               p2);
     return;
   }
 
-  uint8_t module = (uint8_t)(uintptr_t)p1;
   moduleState[module].forced_off = 1;
 
   uint32_t timeout = p2;
@@ -146,18 +148,13 @@ static void _setup_async_module_restart(void* p1, uint32_t p2)
 
   mixerTaskUnlock();
 }
-#endif
 
 // return true if the request could be posted to the timer queue
 bool restartModuleAsync(uint8_t module, uint8_t cnt_delay)
 {
-#if !defined(SIMU)
-  PendedFunction_t cb = _setup_async_module_restart;
-  return xTimerPendFunctionCall(cb, (void*)(uintptr_t)module, cnt_delay,
-                                0/* do not wait */) == pdPASS;
-#else
-  return true;
-#endif
+  void* param1 = (void*)(uintptr_t)module;
+  return async_call(_setup_async_module_restart,
+                    &_module_restart_queued[module], param1, cnt_delay);
 }
 
 void pulsesModuleSettingsUpdate(uint8_t module)
@@ -497,7 +494,7 @@ void pulsesStopModule(uint8_t module)
   while(_telemetryIsPolling) {
     // In case the telemetry timer is currently polling the port,
     // we give the timer task a chance to run and finish the polling.
-    RTOS_WAIT_MS(1);
+    sleep_ms(1);
   }
   _deinit_module(module);
 
diff --git a/radio/src/pulses/pxx2_ota.cpp b/radio/src/pulses/pxx2_ota.cpp
index 7287a5245f4..16db5115472 100644
--- a/radio/src/pulses/pxx2_ota.cpp
+++ b/radio/src/pulses/pxx2_ota.cpp
@@ -21,6 +21,7 @@
 
 #include "edgetx.h"
 #include "io/frsky_firmware_update.h"
+#include "os/sleep.h"
 #include "tasks/mixer_task.h"
 
 #include "pxx2_ota.h"
@@ -37,7 +38,7 @@ bool Pxx2OtaUpdate::waitStep(uint8_t step, uint8_t timeout)
     if (elapsed++ > timeout) {
       return false;
     }
-    RTOS_WAIT_MS(1);
+    sleep_ms(1);
     telemetryWakeup();
   }
 
@@ -135,7 +136,7 @@ void Pxx2OtaUpdate::flashFirmware(const char * filename, ProgressHandler progres
   mixerTaskStop();
 
   watchdogSuspend(100 /*1s*/);
-  RTOS_WAIT_MS(100);
+  sleep_ms(100);
 
   moduleState[module].mode = MODULE_MODE_OTA_UPDATE;
   const char * result = doFlashFirmware(filename, progressHandler);
@@ -152,7 +153,7 @@ void Pxx2OtaUpdate::flashFirmware(const char * filename, ProgressHandler progres
   }
 
   watchdogSuspend(100);
-  RTOS_WAIT_MS(100);
+  sleep_ms(100);
 
   mixerTaskStart();
 }
diff --git a/radio/src/rtos.h b/radio/src/rtos.h
index 705502ddf10..e0beae59caa 100644
--- a/radio/src/rtos.h
+++ b/radio/src/rtos.h
@@ -32,200 +32,25 @@ extern "C++" {
   #include <pthread.h>
   #include <semaphore.h>
 
-  #define SIMU_SLEEP_OR_EXIT_MS(x)       simuSleep(x)
-  #define RTOS_MS_PER_TICK  1
-
-  typedef pthread_t RTOS_TASK_HANDLE;
-  typedef pthread_mutex_t RTOS_MUTEX_HANDLE;
-
-  typedef uint32_t RTOS_FLAG_HANDLE;
-
-  typedef sem_t * RTOS_EVENT_HANDLE;
-
-  extern uint64_t simuTimerMicros(void);
-  extern uint8_t simuSleep(uint32_t ms);
-
   static inline void RTOS_START()
   {
   }
 
-  static inline void RTOS_WAIT_MS(uint32_t x)
-  {
-    simuSleep(x);
-  }
-
-  static inline void RTOS_WAIT_TICKS(uint32_t x)
-  {
-    RTOS_WAIT_MS(x * RTOS_MS_PER_TICK);
-  }
-
-#ifdef __cplusplus
-  static inline void RTOS_CREATE_MUTEX(pthread_mutex_t &mutex)
-  {
-    mutex = PTHREAD_MUTEX_INITIALIZER;
-  }
-
-  static inline bool RTOS_LOCK_MUTEX(pthread_mutex_t &mutex)
-  {
-      return pthread_mutex_lock(&mutex) == 0;
-  }
-
-  static inline bool RTOS_TRYLOCK_MUTEX(pthread_mutex_t &mutex)
-  {
-      return pthread_mutex_trylock(&mutex) == 0;
-  }
-
-  static inline void RTOS_UNLOCK_MUTEX(pthread_mutex_t &mutex)
-  {
-      pthread_mutex_unlock(&mutex);
-  }
-
-  template<int SIZE>
-  class TaskStack
-  {
-    public:
-      TaskStack()
-      {
-      }
-
-      void paint()
-      {
-      }
-
-      uint32_t size()
-      {
-        return SIZE;
-      }
-
-      uint32_t available()
-      {
-        return SIZE / 2;
-      }
-  };
-  #define RTOS_DEFINE_STACK(taskHandle, name, size) TaskStack<size> name
-
-  #define TASK_FUNCTION(task)           void* task(void *)
-
-  inline void RTOS_CREATE_TASK(pthread_t &taskId, void * (*task)(void *), const char * name)
-  {
-    pthread_create(&taskId, nullptr, task, nullptr);
-#ifdef __linux__
-    pthread_setname_np(taskId, name);
-#endif
-  }
-
-  template <int SIZE>
-  inline void RTOS_CREATE_TASK(pthread_t &taskId, void *(*task)(void *),
-                               const char *name, TaskStack<SIZE> &,
-                               unsigned size = 0, unsigned priority = 0)
-  {
-    (void)size;
-    (void)priority;
-    RTOS_CREATE_TASK(taskId, task, name);
-  }
-
-#define TASK_RETURN()                 return nullptr
-
-  constexpr uint32_t mainStackAvailable()
+  static inline uint32_t mainStackAvailable()
   {
     return 500;
   }
-#endif  // __cplusplus
-
-  // return 2ms resolution to match CoOS settings
-  static inline uint32_t RTOS_GET_TIME(void)
-  {
-    return (uint32_t)(simuTimerMicros() / 2000);
-  }
-
-  static inline uint32_t RTOS_GET_MS(void)
-  {
-    return (uint32_t)(simuTimerMicros() / 1000);
-  }
 
 #elif defined(FREE_RTOS)
-#ifdef __cplusplus
-  extern "C" {
-#endif
-    #include <FreeRTOS/include/FreeRTOS.h>
-    #include <FreeRTOS/include/task.h>
-    #include <FreeRTOS/include/semphr.h>
-#ifdef __cplusplus
-  }
-#endif
-
-  #define RTOS_MS_PER_TICK portTICK_PERIOD_MS
-
-  typedef struct {
-    TaskHandle_t rtos_handle;
-    StaticTask_t task_struct;
-  } RTOS_TASK_HANDLE;
 
-  typedef struct {
-    SemaphoreHandle_t rtos_handle;
-    StaticSemaphore_t mutex_struct;
-  } RTOS_MUTEX_HANDLE;
-  
-  typedef RTOS_MUTEX_HANDLE RTOS_FLAG_HANDLE;
+  #include <FreeRTOS/include/FreeRTOS.h>
+  #include <FreeRTOS/include/task.h>
   
   static inline void RTOS_START()
   {
     vTaskStartScheduler();
   }
 
-  static inline void RTOS_WAIT_MS(uint32_t x)
-  {
-    if (!x)
-      return;
-    if ((x = x / RTOS_MS_PER_TICK) < 1)
-      x = 1;
-
-    vTaskDelay(x);
-  }
-
-  static inline void RTOS_WAIT_TICKS(uint32_t x)
-  {
-    vTaskDelay(x);
-  }
-
-  static inline void _RTOS_CREATE_TASK(RTOS_TASK_HANDLE *h,
-                                       TaskFunction_t pxTaskCode,
-                                       const char *name,
-                                       StackType_t *const puxStackBuffer,
-                                       const uint32_t ulStackDepth,
-                                       UBaseType_t uxPriority)
-  {
-    h->rtos_handle = xTaskCreateStatic(
-        pxTaskCode, name, ulStackDepth, NULL, uxPriority,
-        puxStackBuffer, &h->task_struct);
-  }
-
-  #define RTOS_CREATE_TASK(h,task,name,stackStruct,stackSize,prio) \
-    _RTOS_CREATE_TASK(&h,task,name,stackStruct.stack,stackSize,prio)
-  
-  static inline void _RTOS_CREATE_MUTEX(RTOS_MUTEX_HANDLE* h)
-  {
-    h->rtos_handle = xSemaphoreCreateMutexStatic(&h->mutex_struct);
-    xSemaphoreGive(h->rtos_handle);
-  }
-
-  #define RTOS_CREATE_MUTEX(handle) _RTOS_CREATE_MUTEX(&handle)
-
-  static inline bool _RTOS_LOCK_MUTEX(RTOS_MUTEX_HANDLE* h, TickType_t xTickToWait)
-  {
-    return xSemaphoreTake(h->rtos_handle, xTickToWait) == pdTRUE;
-  }
-
-  #define RTOS_LOCK_MUTEX(handle) _RTOS_LOCK_MUTEX(&handle, portMAX_DELAY)
-  #define RTOS_TRYLOCK_MUTEX(handle) _RTOS_LOCK_MUTEX(&handle, (TickType_t)0)
-
-  static inline void _RTOS_UNLOCK_MUTEX(RTOS_MUTEX_HANDLE* h)
-  {
-    xSemaphoreGive(h->rtos_handle);
-  }
-
-  #define RTOS_UNLOCK_MUTEX(handle) _RTOS_UNLOCK_MUTEX(&handle)
-
   static inline uint32_t getStackAvailable(void * address, uint32_t size)
   {
     uint32_t * array = (uint32_t *)address;
@@ -248,77 +73,6 @@ extern "C++" {
     return getStackAvailable(&_main_stack_start, stackSize());
   }
 
-  //#define RTOS_CREATE_FLAG(flag)        flag = CoCreateFlag(false, false)
-  //#define RTOS_SET_FLAG(flag)           (void)CoSetFlag(flag)
-  //#define RTOS_CLEAR_FLAG(flag)         (void)CoClearFlag(flag)
-
-  // returns true if timeout
-  static inline bool _RTOS_WAIT_FLAG(RTOS_FLAG_HANDLE* flag, uint32_t timeout)
-  {
-    return xSemaphoreTake(flag->rtos_handle, timeout * RTOS_MS_PER_TICK)
-      == pdFALSE;
-  }
-
-  #define RTOS_WAIT_FLAG(flag,timeout) _RTOS_WAIT_FLAG(&flag,timeout)
-
-  static inline void _RTOS_ISR_SET_FLAG(RTOS_FLAG_HANDLE* flag)
-  {
-    BaseType_t xHigherPriorityTaskWoken = pdFALSE;
-
-    // Give semaphore back from ISR to trigger a task waiting for it
-    xSemaphoreGiveFromISR( flag->rtos_handle, &xHigherPriorityTaskWoken );
-
-    // If xHigherPriorityTaskWoken was set to true we should yield
-    portYIELD_FROM_ISR( xHigherPriorityTaskWoken );
-  }
-
-  #define RTOS_ISR_SET_FLAG(flag) _RTOS_ISR_SET_FLAG(&flag)
-
-#ifdef __cplusplus
-  template<int SIZE>
-  class TaskStack
-  {
-    public:
-      TaskStack(RTOS_TASK_HANDLE *h) {
-        this->h = h;
-      }
-
-      uint32_t size()
-      {
-        return SIZE * 4;
-      }
-
-      uint32_t available()
-      {
-        return uxTaskGetStackHighWaterMark(h->rtos_handle);
-      }
-
-      StackType_t stack[SIZE];
-    protected:
-      RTOS_TASK_HANDLE *h;
-  };
-#endif // __cplusplus
-
-  static inline TickType_t RTOS_GET_TIME(void)
-  {
-    return xTaskGetTickCount();
-  }
-
-  static inline uint32_t RTOS_GET_MS(void)
-  {
-    return (RTOS_GET_TIME() * RTOS_MS_PER_TICK);
-  }
-
-  // stack must be aligned to 8 bytes otherwise printf for %f does not work!
-  #define RTOS_DEFINE_STACK(taskHandle, name, size) TaskStack<size> __ALIGNED(8) name __CCMRAM (&taskHandle) 
-
-  #define TASK_FUNCTION(task)           void task(void *)
-  #define TASK_RETURN()                 vTaskDelete(nullptr)
-
-#else // no RTOS
-
-  #error "No RTOS implementation defined"
-
 #endif  // RTOS type
 
 #ifdef __cplusplus
diff --git a/radio/src/simu.cpp b/radio/src/simu.cpp
index 5cf6e578a70..65e735e2703 100644
--- a/radio/src/simu.cpp
+++ b/radio/src/simu.cpp
@@ -37,6 +37,8 @@
 #include "hal/adc_driver.h"
 #include "hal/rotary_encoder.h"
 
+#include "os/time.h"
+
 #if LCD_W > 212
   #define LCD_ZOOM 1
 #else
@@ -166,7 +168,6 @@ OpenTxSim::~OpenTxSim()
   TRACE("OpenTxSim::~OpenTxSim()");
 
   simuStop();
-  stopAudioThread();
 
   delete bmp;
   delete sliders[0];
@@ -492,7 +493,7 @@ long OpenTxSim::onTimeout(FXObject*, FXSelector, void*)
 
     static uint32_t last_tick = 0;
     if (rotencAction) {
-      uint32_t now = RTOS_GET_MS();
+      uint32_t now = time_get_ms();
       uint32_t dt = now - last_tick;
       rotencDt += dt;
       last_tick = now;
@@ -500,12 +501,11 @@ long OpenTxSim::onTimeout(FXObject*, FXSelector, void*)
 #endif
   }
 
-#if !defined(SIMU_BOOTLOADER)
-  per10ms();
-#else
+#if defined(SIMU_BOOTLOADER)
   void interrupt10ms();
   interrupt10ms();
 #endif
+
   refreshDisplay();
   getApp()->addTimeout(this, 2, 10);
   return 0;
@@ -644,8 +644,9 @@ int main(int argc, char ** argv)
   printf("Model size = %d\n", (int)sizeof(g_model));
 
 #if !defined(SIMU_BOOTLOADER)
-  startAudioThread();
+  startAudio();
 #endif
+
   simuStart(true/*false*/, argc >= 3 ? argv[2] : 0, argc >= 4 ? argv[3] : 0);
 
   return application.run();
diff --git a/radio/src/spacemouse.cpp b/radio/src/spacemouse.cpp
index 74828f8256a..c09657852f5 100644
--- a/radio/src/spacemouse.cpp
+++ b/radio/src/spacemouse.cpp
@@ -20,13 +20,8 @@
  */
 
 #include "edgetx.h"
-// #include <ctype.h>
 #include "tasks/mixer_task.h"
-
-#if !defined(SIMU)
-  #include <FreeRTOS/include/FreeRTOS.h>
-  #include <FreeRTOS/include/timers.h>
-#endif
+#include "os/timer.h"
 
 struct spacemousedata_t
 {
@@ -57,11 +52,9 @@ spacemousedata_t spacemouseData;
 
 void spacemouseWakeup();
 
-#if !defined(SIMU)
-static TimerHandle_t spacemouseTimer = nullptr;
-static StaticTimer_t spacemouseTimerBuffer;
+static timer_handle_t spacemouseTimer = TIMER_INITIALIZER;
 
-static void spacemouseTimerCb(TimerHandle_t xTimer)
+static void spacemouseTimerCb(timer_handle_t* timer)
 {
   if (mixerTaskRunning()) {
     DEBUG_TIMER_START(debugTimerSpacemouseWakeup);
@@ -73,28 +66,17 @@ static void spacemouseTimerCb(TimerHandle_t xTimer)
 
 void spacemouseStart()
 {
-  if (!spacemouseTimer) {
-    spacemouseTimer =
-        xTimerCreateStatic("SpaceM", 10 / RTOS_MS_PER_TICK, pdTRUE, (void*)0,
-                           spacemouseTimerCb, &spacemouseTimerBuffer);
+  if (!timer_is_created(&spacemouseTimer)) {
+    timer_create(&spacemouseTimer, spacemouseTimerCb, "spacem", 10, true);
   }
 
-  if (spacemouseTimer) {
-    if( xTimerStart( spacemouseTimer, 0 ) != pdPASS ) {
-      /* The timer could not be set into the Active state. */
-    }
-  }
+  timer_start(&spacemouseTimer);
 }
 
 void spacemouseStop()
 {
-  if (spacemouseTimer) {
-    if( xTimerStop( spacemouseTimer, 12 / RTOS_MS_PER_TICK ) != pdPASS ) {
-      /* The timer could not be stopped. */
-    }
-  }
+  timer_stop(&spacemouseTimer);
 }
-#endif
 
 void spacemouseParseNewData(uint8_t c)
 {
@@ -155,9 +137,7 @@ void spacemouseSetSerialDriver(void* ctx, const etx_serial_driver_t* drv)
   spacemouseSerialCtx = ctx;
   spacemouseSerialDrv = drv;
   spaceMouseTelegram.parsestate = sm_bytetype::SM_START;
-#if !defined(SIMU)
   spacemouseStart();
-#endif
 }
 
 int16_t get_spacemouse_value(uint8_t ch)
diff --git a/radio/src/storage/modelslist.cpp b/radio/src/storage/modelslist.cpp
index f7895c9ac37..d7370d2ac2a 100644
--- a/radio/src/storage/modelslist.cpp
+++ b/radio/src/storage/modelslist.cpp
@@ -31,6 +31,7 @@ using std::list;
 #include "yaml/yaml_labelslist.h"
 #include "yaml/yaml_modelslist.h"
 #include "yaml/yaml_parser.h"
+#include "os/sleep.h"
 
 #if defined(USBJ_EX)
 #include "usb_joystick.h"
@@ -727,7 +728,7 @@ bool ModelMap::renameLabel(const std::string &from, std::string to,
                              (uint8_t *)modeldata, 0) != NULL);
     }
 #if defined(SIMU)
-    if (SIMU_SLEEP_OR_EXIT_MS(100)) break;
+    sleep_ms(100);
 #endif
   }
 
diff --git a/radio/src/storage/storage_common.cpp b/radio/src/storage/storage_common.cpp
index 2fec387a5cd..72e3bdc39e2 100644
--- a/radio/src/storage/storage_common.cpp
+++ b/radio/src/storage/storage_common.cpp
@@ -20,6 +20,7 @@
  */
 
 #include "edgetx.h"
+#include "os/sleep.h"
 #include "timers_driver.h"
 #include "tasks/mixer_task.h"
 #include "mixes.h"
@@ -76,8 +77,9 @@ void preModelLoad()
   LayoutFactory::deleteCustomScreens(true);
 #endif
 
-  if (needDelay)
-    RTOS_WAIT_MS(200);
+  if (needDelay) {
+    sleep_ms(200);
+  }
 }
 
 void postRadioSettingsLoad()
diff --git a/radio/src/switches.cpp b/radio/src/switches.cpp
index 2d06c9d3bc5..752d9c824ae 100644
--- a/radio/src/switches.cpp
+++ b/radio/src/switches.cpp
@@ -26,6 +26,7 @@
 #include "myeeprom.h"
 #include "edgetx.h"
 #include "edgetx_constants.h"
+#include "os/sleep.h"
 #include "switches.h"
 #include "input_mapping.h"
 #include "inactivity_timer.h"
@@ -1051,8 +1052,7 @@ void checkSwitches()
     checkBacklight();
 
     WDG_RESET();
-
-    RTOS_WAIT_MS(10);
+    sleep_ms(10);
   }
 
   LED_ERROR_END();
diff --git a/radio/src/targets/common/arm/stm32/audio_dac_driver.cpp b/radio/src/targets/common/arm/stm32/audio_dac_driver.cpp
index 48f8d174a8b..80a49d0a953 100644
--- a/radio/src/targets/common/arm/stm32/audio_dac_driver.cpp
+++ b/radio/src/targets/common/arm/stm32/audio_dac_driver.cpp
@@ -22,6 +22,7 @@
 #include "hal/gpio.h"
 #include "hal/audio_driver.h"
 
+#include "os/sleep.h"
 #include "stm32_gpio.h"
 #include "stm32_timer.h"
 #include "stm32_dma.h"
@@ -162,7 +163,7 @@ void audioUnmute()
   if (get_mute_pin()) {
     // ..un-mute
     set_mute_pin(false);
-    RTOS_WAIT_MS(AUDIO_UNMUTE_DELAY);
+    sleep_ms(AUDIO_UNMUTE_DELAY);
   }
   // reset the mute delay
   audioQueue.lastAudioPlayTime = 0;
diff --git a/radio/src/targets/common/arm/stm32/bootloader/CMakeLists.txt b/radio/src/targets/common/arm/stm32/bootloader/CMakeLists.txt
index 874f07fe847..5bf7ea35490 100644
--- a/radio/src/targets/common/arm/stm32/bootloader/CMakeLists.txt
+++ b/radio/src/targets/common/arm/stm32/bootloader/CMakeLists.txt
@@ -6,6 +6,8 @@ AddHWGenTarget(${HW_DESC_JSON} hal_keys hal_keys.inc)
 
 set(BOOTLOADER_SRC ${BOOTLOADER_SRC}
   ${CMAKE_CURRENT_BINARY_DIR}/hal_keys.inc
+  ${RADIO_SRC_DIR}/os/time_nortos.cpp
+  ${RADIO_SRC_DIR}/os/sleep_nortos.cpp
   ${RADIO_SRC_DIR}/keys.cpp
   ${RADIO_SRC_DIR}/strhelpers.cpp
   ${RADIO_SRC_DIR}/stamp.cpp
diff --git a/radio/src/targets/common/arm/stm32/bootloader/boot.cpp b/radio/src/targets/common/arm/stm32/bootloader/boot.cpp
index 31835fca7b6..c9b93c9db93 100644
--- a/radio/src/targets/common/arm/stm32/bootloader/boot.cpp
+++ b/radio/src/targets/common/arm/stm32/bootloader/boot.cpp
@@ -135,6 +135,11 @@ void bootloaderInitApp()
   boardBLInit();
 }
 
+#if defined(FIRMWARE_FORMAT_UF2)
+// make linker happy
+void per5ms() {}
+#endif
+
 int main()
 #else // SIMU
 void bootloaderInitApp() {}
diff --git a/radio/src/targets/common/arm/stm32/bootloader/boot_dfu.cpp b/radio/src/targets/common/arm/stm32/bootloader/boot_dfu.cpp
index fdf8177a7cc..918d938fc60 100644
--- a/radio/src/targets/common/arm/stm32/bootloader/boot_dfu.cpp
+++ b/radio/src/targets/common/arm/stm32/bootloader/boot_dfu.cpp
@@ -2,9 +2,11 @@
 
 #include "boot.h"
 #include "hal/usb_driver.h"
+#include "os/time.h"
+
 #include "lcd.h"
 
-extern volatile uint8_t tenms;
+#define FRAME_INTERVAL_MS 20
 
 void bootloaderDFU()
 {
@@ -13,8 +15,11 @@ void bootloaderDFU()
 
   bootloaderDrawDFUScreen();
 
+  uint32_t next_frame = time_get_ms();
   for (;;) {
-    if (tenms) {
+    if (time_get_ms() - next_frame >= FRAME_INTERVAL_MS) {
+      next_frame += FRAME_INTERVAL_MS;
+
       if (!usbPlugged()) break;
       bootloaderDrawDFUScreen();
       lcdRefresh();
diff --git a/radio/src/targets/common/arm/stm32/bootloader/boot_menu.cpp b/radio/src/targets/common/arm/stm32/bootloader/boot_menu.cpp
index a519a1f1963..c0c62ddf310 100644
--- a/radio/src/targets/common/arm/stm32/bootloader/boot_menu.cpp
+++ b/radio/src/targets/common/arm/stm32/bootloader/boot_menu.cpp
@@ -3,9 +3,12 @@
 
 #include "hal/usb_driver.h"
 #include "hal/rotary_encoder.h"
+#include "os/time.h"
 
 #include "lcd.h"
 
+#define FRAME_INTERVAL_MS 20
+
 #if defined(SPI_FLASH)
   #define MAIN_MENU_LEN 3
 #else
@@ -17,16 +20,8 @@
   #define SEL_CLEAR_FLASH_STORAGE_MENU_LEN 2
 #endif
 
-volatile tmr10ms_t g_tmr10ms;
-volatile uint8_t tenms = 1;
-
-void per5ms() {} // make linker happy
-
-void per10ms()
+void pollInputs()
 {
-  tenms |= 1u; // 10 mS has passed
-  g_tmr10ms++;
-
   keysPollingCycle();
 
   // TODO: use rotaryEncoderPollingCycle() instead
@@ -42,6 +37,13 @@ void per10ms()
 #endif
 }
 
+// poll inputs every 10ms
+void per5ms()
+{
+  static uint32_t cnt = 0;
+  if (++cnt & 1) { pollInputs(); }
+}
+
 FlashCheckRes valid;
 
 int menuFlashFile(uint32_t index, event_t event)
@@ -74,10 +76,12 @@ void bootloaderMenu()
   
   sdInit();
 
+  uint32_t next_frame = time_get_ms();
+
   for (;;) {
 
-    if (tenms) {
-      tenms = 0;
+    if (time_get_ms() - next_frame >= FRAME_INTERVAL_MS) {
+      next_frame += FRAME_INTERVAL_MS;
 
       if (state != ST_USB && state != ST_FLASHING
           && state != ST_FLASH_DONE && state != ST_RADIO_MENU) {
diff --git a/radio/src/targets/common/arm/stm32/bootloader/boot_uf2.cpp b/radio/src/targets/common/arm/stm32/bootloader/boot_uf2.cpp
index 01ca1ea503f..0d8ba745148 100644
--- a/radio/src/targets/common/arm/stm32/bootloader/boot_uf2.cpp
+++ b/radio/src/targets/common/arm/stm32/bootloader/boot_uf2.cpp
@@ -3,6 +3,7 @@
 #include "hal/usb_driver.h"
 #include "hal/storage.h"
 #include "hal/fatfs_diskio.h"
+#include "os/time.h"
 
 #include "thirdparty/FatFs/diskio.h"
 #include "drivers/uf2_ghostfat.h"
@@ -10,18 +11,9 @@
 #include "board.h"
 #include "lcd.h"
 
-extern uf2_fat_write_state_t _uf2_write_state;
-
-volatile tmr10ms_t g_tmr10ms;
-volatile uint8_t tenms = 1;
+#define FRAME_INTERVAL_MS 20
 
-void per5ms() {} // make linker happy
-
-void per10ms()
-{
-  tenms |= 1u; // 10 mS has passed
-  g_tmr10ms++;
-}
+extern uf2_fat_write_state_t _uf2_write_state;
 
 void bootloaderUF2()
 {
@@ -31,10 +23,12 @@ void bootloaderUF2()
   storageInit();
   disk_initialize(0);
 
+  uint32_t next_frame = time_get_ms();
+
   for (;;) {
 
-    if (tenms) {
-      tenms = 0;
+    if (time_get_ms() - next_frame >= FRAME_INTERVAL_MS) {
+      next_frame += FRAME_INTERVAL_MS;
 
       if (state != ST_USB && state != ST_FLASHING && state != ST_FLASH_DONE) {
         if (usbPlugged()) {
diff --git a/radio/src/targets/common/arm/stm32/rotary_encoder_driver.cpp b/radio/src/targets/common/arm/stm32/rotary_encoder_driver.cpp
index 4faac300681..a26f768e96d 100644
--- a/radio/src/targets/common/arm/stm32/rotary_encoder_driver.cpp
+++ b/radio/src/targets/common/arm/stm32/rotary_encoder_driver.cpp
@@ -137,7 +137,7 @@ void rotaryEncoderCheck()
   rotenc_t diff = (value - last_value);
 
   if (diff != 0) {
-    uint32_t now = RTOS_GET_MS();
+    uint32_t now = timersGetMsTick();
     uint32_t dt = now - last_tick;
     // pre-compute accumulated dt (dx/dt is done later in LVGL driver)
     rotencDt += dt;
diff --git a/radio/src/targets/common/arm/stm32/timers_driver.cpp b/radio/src/targets/common/arm/stm32/timers_driver.cpp
index bcb98170111..9cca5d0f663 100644
--- a/radio/src/targets/common/arm/stm32/timers_driver.cpp
+++ b/radio/src/targets/common/arm/stm32/timers_driver.cpp
@@ -100,8 +100,6 @@ static inline void _interrupt_1ms()
       watchdogTimeout -= 1;
       WDG_RESET();  // Retrigger hardware watchdog
     }
-
-    per10ms();
   }
 }
 
diff --git a/radio/src/targets/common/arm/stm32/vs1053b.cpp b/radio/src/targets/common/arm/stm32/vs1053b.cpp
index f86f3033649..829378f0ba1 100644
--- a/radio/src/targets/common/arm/stm32/vs1053b.cpp
+++ b/radio/src/targets/common/arm/stm32/vs1053b.cpp
@@ -21,6 +21,7 @@
 
 #include "vs1053b.h"
 
+#include "os/sleep.h"
 #include "stm32_hal_ll.h"
 #include "stm32_gpio_driver.h"
 #include "stm32_gpio.h"
@@ -327,7 +328,7 @@ static void vs1053b_unmute()
     if (_is_muted) {
       // ..un-mute
       _set_mute_pin(false);
-      RTOS_WAIT_MS(_instance->unmute_delay_ms);
+      sleep_ms(_instance->unmute_delay_ms);
     }
     // reset the mute delay
     _last_play_ts = 0;
diff --git a/radio/src/targets/horus/cst8xx_driver.cpp b/radio/src/targets/horus/cst8xx_driver.cpp
index 36ac8426d77..71092978cd1 100644
--- a/radio/src/targets/horus/cst8xx_driver.cpp
+++ b/radio/src/targets/horus/cst8xx_driver.cpp
@@ -42,8 +42,8 @@ volatile static bool touchEventOccured;
 
 static tc_handle_TypeDef tc_handle = {0, 0};
 
-tmr10ms_t downTime = 0;
-tmr10ms_t tapTime = 0;
+uint32_t downTime = 0;
+uint32_t tapTime = 0;
 short tapCount = 0;
 #define TAP_TIME 250  // ms
 
@@ -251,7 +251,7 @@ TouchState touchPanelRead()
 
   touchEventOccured = false;
 
-  tmr10ms_t now = RTOS_GET_MS();
+  uint32_t now = timersGetMsTick();
   internalTouchState.tapCount = 0;
 
   if (cst836u_TS_DetectTouch()) {
diff --git a/radio/src/targets/horus/tp_gt911.cpp b/radio/src/targets/horus/tp_gt911.cpp
index 47bab716a91..6e6d21a5277 100644
--- a/radio/src/targets/horus/tp_gt911.cpp
+++ b/radio/src/targets/horus/tp_gt911.cpp
@@ -29,10 +29,11 @@
 #include "stm32_exti_driver.h"
 
 #include "hal.h"
+#include "timers_driver.h"
 #include "tp_gt911.h"
 #include "delays_driver.h"
 
-#include "rtos.h"
+#include "os/sleep.h"
 #include "edgetx_types.h"
 #include "debug.h"
 
@@ -651,7 +652,7 @@ struct TouchState touchPanelRead()
 
   touchEventOccured = false;
 
-  uint32_t startReadStatus = RTOS_GET_MS();
+  uint32_t startReadStatus = timersGetMsTick();
   do {
     if (!I2C_GT911_ReadRegister(GT911_READ_XY_REG, &state, 1)) {
       // ledRed();
@@ -665,15 +666,15 @@ struct TouchState touchPanelRead()
       // ready
       break;
     }
-    RTOS_WAIT_MS(1);
-  } while (RTOS_GET_MS() - startReadStatus < GT911_TIMEOUT);
+    sleep_ms(1);
+  } while (timersGetMsTick() - startReadStatus < GT911_TIMEOUT);
 
   internalTouchState.deltaX = 0;
   internalTouchState.deltaY = 0;
   TRACE("touch state = 0x%x", state);
   if (state & 0x80u) {
     uint8_t pointsCount = (state & 0x0Fu);
-    uint32_t now = RTOS_GET_MS();
+    uint32_t now = timersGetMsTick();
     internalTouchState.tapCount = 0;
 
     if (pointsCount > 0 && pointsCount <= GT911_MAX_TP) {
diff --git a/radio/src/targets/simu/CMakeLists.txt b/radio/src/targets/simu/CMakeLists.txt
index 664aa930305..a97d2899c94 100644
--- a/radio/src/targets/simu/CMakeLists.txt
+++ b/radio/src/targets/simu/CMakeLists.txt
@@ -7,7 +7,6 @@ endif()
 
 set(SIMU_DRIVERS
   simpgmspace.cpp
-  simueeprom.cpp
   simufatfs.cpp
   simudisk.cpp
   simulcd.cpp
@@ -186,7 +185,7 @@ if(FOX_FOUND)
 
   target_include_directories(simu PUBLIC ${FOX_INCLUDE_DIR} )
   target_link_libraries(simu ${FOX_LIBRARY} pthread ${SDL2_LIBRARIES})
-  target_compile_options(simu PRIVATE -DSIMU)
+  target_compile_options(simu PRIVATE ${SIMU_SRC_OPTIONS})
 endif()
 
 if(APPLE)
diff --git a/radio/src/targets/simu/opentxsimulator.cpp b/radio/src/targets/simu/opentxsimulator.cpp
index 0254f04c7e2..0d84baf4d05 100644
--- a/radio/src/targets/simu/opentxsimulator.cpp
+++ b/radio/src/targets/simu/opentxsimulator.cpp
@@ -28,6 +28,7 @@
 
 #include "hal/adc_driver.h"
 #include "hal/rotary_encoder.h"
+#include "os/time.h"
 
 #include <QDebug>
 #include <QElapsedTimer>
@@ -270,9 +271,9 @@ void OpenTxSimulator::start(const char * filename, bool tests)
 
   QMutexLocker lckr(&m_mtxSimuMain);
   QMutexLocker slckr(&m_mtxSettings);
-  startEepromThread(filename);
-  startAudioThread(volumeGain);
-  simuStart(tests, simuSdDirectory.toLatin1().constData(), simuSettingsDirectory.toLatin1().constData());
+  startAudio(volumeGain);
+  simuStart(tests, simuSdDirectory.toLatin1().constData(),
+            simuSettingsDirectory.toLatin1().constData());
 
   emit started();
   QTimer::singleShot(0, this, SLOT(run()));  // old style for Qt < 5.4
@@ -288,8 +289,6 @@ void OpenTxSimulator::stop()
 
   QMutexLocker lckr(&m_mtxSimuMain);
   simuStop();
-  stopAudioThread();
-  stopEepromThread();
 
   emit stopped();
 }
@@ -309,20 +308,20 @@ void OpenTxSimulator::setVolumeGain(const int value)
 
 void OpenTxSimulator::setRadioData(const QByteArray & data)
 {
-#if defined(EEPROM_SIZE)
-  QMutexLocker lckr(&m_mtxRadioData);
-  eeprom = (uint8_t *)malloc(qMin<int>(EEPROM_SIZE, data.size()));
-  memcpy(eeprom, data.data(), qMin<int>(EEPROM_SIZE, data.size()));
-#endif
+// #if defined(EEPROM_SIZE)
+//   QMutexLocker lckr(&m_mtxRadioData);
+//   eeprom = (uint8_t *)malloc(qMin<int>(EEPROM_SIZE, data.size()));
+//   memcpy(eeprom, data.data(), qMin<int>(EEPROM_SIZE, data.size()));
+// #endif
 }
 
 void OpenTxSimulator::readRadioData(QByteArray & dest)
 {
-#if defined(EEPROM_SIZE)
-  QMutexLocker lckr(&m_mtxRadioData);
-  if (eeprom)
-    memcpy(dest.data(), eeprom, qMin<int>(EEPROM_SIZE, dest.size()));
-#endif
+// #if defined(EEPROM_SIZE)
+//   QMutexLocker lckr(&m_mtxRadioData);
+//   if (eeprom)
+//     memcpy(dest.data(), eeprom, qMin<int>(EEPROM_SIZE, dest.size()));
+// #endif
 }
 
 uint8_t * OpenTxSimulator::getLcd()
@@ -416,7 +415,7 @@ void OpenTxSimulator::rotaryEncoderEvent(int steps)
       steps *= -1;
     rotencValue += steps * ROTARY_ENCODER_GRANULARITY;
     // TODO: set rotencDt
-    uint32_t now = RTOS_GET_MS();
+    uint32_t now = time_get_ms();
     uint32_t dt = now - last_tick;
     rotencDt += dt;
     last_tick = now;
@@ -759,8 +758,6 @@ void OpenTxSimulator::run()
 
   ++loops;
 
-  per10ms();
-
   checkLcdChanged();
 
   if (!(loops % 5)) {
diff --git a/radio/src/targets/simu/simpgmspace.cpp b/radio/src/targets/simu/simpgmspace.cpp
index eecbf0c5369..4ca92e6dfe9 100644
--- a/radio/src/targets/simu/simpgmspace.cpp
+++ b/radio/src/targets/simu/simpgmspace.cpp
@@ -34,6 +34,9 @@
 #include "hal/usb_driver.h"
 #include "hal/audio_driver.h"
 
+#include "os/task.h"
+#include "os/timer_pthread_impl.h"
+
 #include <errno.h>
 #include <stdarg.h>
 #include <string>
@@ -211,6 +214,7 @@ void simuStart(bool tests, const char * sdPath, const char * settingsPath)
   lcdInit();
 
 #if !defined(SIMU_BOOTLOADER)
+  timer_queue::instance().start();
   simuMain();
 #else
   pthread_attr_t attr;
@@ -232,8 +236,8 @@ void simuStart(bool tests, const char * sdPath, const char * settingsPath)
 #endif
 }
 
-extern RTOS_TASK_HANDLE mixerTaskId;
-extern RTOS_TASK_HANDLE menusTaskId;
+extern task_handle_t mixerTaskId;
+extern task_handle_t menusTaskId;
 
 void simuStop()
 {
@@ -242,8 +246,12 @@ void simuStop()
 
   simu_shutdown = true;
 
-  pthread_join(mixerTaskId, nullptr);
-  pthread_join(menusTaskId, nullptr);
+  pthread_join(mixerTaskId._thread_handle, nullptr);
+  pthread_join(menusTaskId._thread_handle, nullptr);
+
+#if defined(SIMU_AUDIO)
+  stopAudio();
+#endif
 
   simu_running = false;
 }
@@ -253,8 +261,6 @@ struct SimulatorAudio {
   int currentVolume;
   int16_t leftoverData[AUDIO_BUFFER_SIZE];
   int leftoverLen;
-  bool threadRunning;
-  pthread_t threadPid;
 } simuAudio;
 
 bool simuIsRunning()
@@ -264,10 +270,9 @@ bool simuIsRunning()
 
 uint8_t simuSleep(uint32_t ms)
 {
-  for (uint32_t i = 0; i < ms; ++i){
-    if (simu_shutdown || !simu_running)
-      return 1;
-    sleep(1);
+  for (uint32_t i = 0; i < ms; i++) {
+    if (simu_shutdown || !simu_running) return 1;
+    usleep(1);
   }
   return 0;
 }
@@ -336,77 +341,44 @@ void fillAudioBuffer(void *udata, Uint8 *stream, int len)
     }
   }
 
-  //fill the rest of buffer with silence
+  // fill the rest of buffer with silence
   if (len > 0) {
     SDL_memset(stream, 0x8000, len);  // make sure this is silence.
-    // putchar('.');
   }
 }
 
-void * audioThread(void *)
+int startAudio(int volumeGain)
 {
-  /*
-    Checking here if SDL audio was initialized is wrong, because
-    the SDL_CloseAudio() de-initializes it.
-
-    if ( !SDL_WasInit(SDL_INIT_AUDIO) ) {
-      fprintf(stderr, "ERROR: couldn't initialize SDL audio support\n");
-      return 0;
-    }
-  */
+  simuAudio = {
+    .volumeGain = volumeGain,
+    .leftoverLen = 0,
+  };
 
-  SDL_AudioSpec wanted, have;
+  TRACE("startAudioThread(%d)", volumeGain);
+  audioSetVolume(VOLUME_LEVEL_DEF);
 
   /* Set the audio format */
-  wanted.freq = AUDIO_SAMPLE_RATE;
-  wanted.format = AUDIO_S16SYS;
-  wanted.channels = 1;    /* 1 = mono, 2 = stereo */
-  wanted.samples =
-      AUDIO_BUFFER_SIZE * 2; /* Good low-latency value for callback */
-  wanted.callback = fillAudioBuffer;
-  wanted.userdata = nullptr;
-
-  /*
-    SDL_OpenAudio() internally calls SDL_InitSubSystem(SDL_INIT_AUDIO),
-    which initializes SDL Audio subsystem if necessary
-  */
-  if ( SDL_OpenAudio(&wanted, &have) < 0 ) {
+  SDL_AudioSpec desired = {
+    .freq = AUDIO_SAMPLE_RATE,
+    .format = AUDIO_S16SYS,
+    .channels = 1,
+    .samples = AUDIO_BUFFER_SIZE * 2,
+    .callback = fillAudioBuffer,
+    .userdata = nullptr,
+  };
+
+  SDL_AudioSpec obtained;
+  if ( SDL_OpenAudio(&desired, &obtained) < 0 ) {
     fprintf(stderr, "Couldn't open audio: %s\n", SDL_GetError());
-    return nullptr;
+    return -1;
   }
   SDL_PauseAudio(0);
-
-  while (simuAudio.threadRunning) {
-    audioQueue.wakeup();
-    sleep(1);
-  }
-  SDL_CloseAudio();
-  return nullptr;
-}
-
-void startAudioThread(int volumeGain)
-{
-  simuAudio.leftoverLen = 0;
-  simuAudio.threadRunning = true;
-  simuAudio.volumeGain = volumeGain;
-  TRACE_SIMPGMSPACE("startAudioThread(%d)", volumeGain);
-  audioSetVolume(VOLUME_LEVEL_DEF);
-
-  pthread_attr_t attr;
-  pthread_attr_init(&attr);
-  struct sched_param sp;
-  sp.sched_priority = SCHED_RR;
-  pthread_attr_setschedparam(&attr, &sp);
-  pthread_create(&simuAudio.threadPid, &attr, &audioThread, nullptr);
-#ifdef __linux__
-  pthread_setname_np(simuAudio.threadPid, "audio");
-#endif
+  return 0;
 }
 
-void stopAudioThread()
+void stopAudio()
 {
-  simuAudio.threadRunning = false;
-  pthread_join(simuAudio.threadPid, nullptr);
+  SDL_CloseAudio();
 }
 #endif // #if defined(SIMU_AUDIO)
 
@@ -675,6 +647,3 @@ struct TouchState getInternalTouchState()
   return simTouchState;
 }
 #endif
-
-void telemetryStart() {}
-void telemetryStop() {}
diff --git a/radio/src/targets/simu/simpgmspace.h b/radio/src/targets/simu/simpgmspace.h
index e18aebdbf89..b54afa439d3 100644
--- a/radio/src/targets/simu/simpgmspace.h
+++ b/radio/src/targets/simu/simpgmspace.h
@@ -30,17 +30,11 @@
 #include <stddef.h>
 #include <errno.h>
 
-// #undef min
-// #undef max
-
-extern uint8_t * eeprom;
-
 #define __disable_irq()
 #define __enable_irq()
 
 extern char * main_thread_error;
 
-
 uint64_t simuTimerMicros(void);
 uint8_t simuSleep(uint32_t ms);  // returns true if thread shutdown requested
 
@@ -57,21 +51,16 @@ void startEepromThread(const char * filename = "eeprom.bin");
 void stopEepromThread();
 
 #if defined(SIMU_AUDIO)
-  void startAudioThread(int volumeGain = 10);
-  void stopAudioThread(void);
+  int startAudio(int volumeGain = 10);
+  void stopAudio();
 #else
-  #define startAudioThread(dummy)
-  #define stopAudioThread()
+  #define startAudio(dummy) (-1)
+  #define stopAudio()
 #endif
 #endif
 
 void simuMain();
 
-
-// inline void delay_01us(uint32_t dummy) { }
-
-#define configure_pins(...)
-
 #if !defined(SKIP_FATFS_DECLARATION) && !defined(SIMU_DISKIO)
   #define SIMU_USE_SDCARD
 #endif
diff --git a/radio/src/targets/stm32h7s78-dk/tp_gt911.cpp b/radio/src/targets/stm32h7s78-dk/tp_gt911.cpp
index d6966548a95..d4936b7213f 100644
--- a/radio/src/targets/stm32h7s78-dk/tp_gt911.cpp
+++ b/radio/src/targets/stm32h7s78-dk/tp_gt911.cpp
@@ -19,6 +19,7 @@
  * GNU General Public License for more details.
  */
 
+#include "os/sleep.h"
 #include "stm32_hal_ll.h"
 #include "stm32_hal.h"
 #include "stm32_i2c_driver.h"
@@ -32,6 +33,7 @@
 #include "hal.h"
 
 #include "stm32h7rsxx_hal_gpio.h"
+#include "timers_driver.h"
 #include "tp_gt911.h"
 #include "delays_driver.h"
 
@@ -215,7 +217,7 @@ struct TouchState touchPanelRead()
 
   touchEventOccured = false;
 
-  uint32_t startReadStatus = RTOS_GET_MS();
+  uint32_t startReadStatus = timersGetMsTick();
   do {
     if (!I2C_GT911_ReadRegister(GT911_READ_XY_REG, &state, 1)) {
       // ledRed();
@@ -229,15 +231,15 @@ struct TouchState touchPanelRead()
       // ready
       break;
     }
-    RTOS_WAIT_MS(1);
-  } while (RTOS_GET_MS() - startReadStatus < GT911_TIMEOUT);
+    sleep_ms(1);
+  } while (timersGetMsTick() - startReadStatus < GT911_TIMEOUT);
 
   internalTouchState.deltaX = 0;
   internalTouchState.deltaY = 0;
   TRACE("touch state = 0x%x", state);
   if (state & 0x80u) {
     uint8_t pointsCount = (state & 0x0Fu);
-    uint32_t now = RTOS_GET_MS();
+    uint32_t now = timersGetMsTick();
     internalTouchState.tapCount = 0;
 
     if (pointsCount > 0 && pointsCount <= GT911_MAX_TP) {
diff --git a/radio/src/targets/taranis/gx12/bsp_io.cpp b/radio/src/targets/taranis/gx12/bsp_io.cpp
index 235f575c1ac..4695e57de0c 100644
--- a/radio/src/targets/taranis/gx12/bsp_io.cpp
+++ b/radio/src/targets/taranis/gx12/bsp_io.cpp
@@ -20,17 +20,17 @@
  */
 
 #include "bsp_io.h"
+#include "hal/switch_driver.h"
+#include "drivers/pca95xx.h"
+#include "os/async.h"
+#include "stm32_i2c_driver.h"
+#include "timers_driver.h"
+#include "stm32_ws2812.h"
 
 #include <FreeRTOS/include/FreeRTOS.h>
 #include <FreeRTOS/include/timers.h>
 
-#include "bitfield.h"
-#include "drivers/pca95xx.h"
-#include "hal/switch_driver.h"
 #include "myeeprom.h"
-#include "stm32_i2c_driver.h"
-#include "stm32_ws2812.h"
-#include "timers_driver.h"
 
 struct bsp_io_expander {
   pca95xx_t exp;
@@ -58,30 +58,18 @@ static uint32_t _read_io_expander(bsp_io_expander* io)
   return io->state;  
 }
 
-static void _poll_switches(void *pvParameter1, uint32_t ulParameter2)
+static void _poll_switches(void *param1, uint32_t param2)
 {
-  (void)ulParameter2;
+  (void)param1;
+  (void)param2;
   _poll_switches_in_queue = false;
-  bsp_io_read_switches();
-  bsp_io_read_fs_switches();
+  _read_io_expander(&_io_switches); 
+  _read_io_expander(&_io_fs_switches); 
 }
 
 static void _io_int_handler()
 {
-  BaseType_t xHigherPriorityTaskWoken = pdFALSE;
-  BaseType_t xReturn = pdFALSE;
-
-  if (!_poll_switches_in_queue && xTaskGetSchedulerState() != taskSCHEDULER_NOT_STARTED) {
-    xReturn = xTimerPendFunctionCallFromISR(_poll_switches, nullptr, 0,
-                                  &xHigherPriorityTaskWoken);
-
-    if (xReturn == pdPASS) {
-      _poll_switches_in_queue = true;
-    } else {
-       TRACE("xTimerPendFunctionCallFromISR() queue full");
-    }
-    portYIELD_FROM_ISR(xHigherPriorityTaskWoken);
-  }
+  async_call_isr(_poll_switches, &_poll_switches_in_queue, nullptr, 0);
 }
 
 int bsp_io_init()
diff --git a/radio/src/tasks.cpp b/radio/src/tasks.cpp
index 8944f6039b5..2d8804fc018 100644
--- a/radio/src/tasks.cpp
+++ b/radio/src/tasks.cpp
@@ -19,7 +19,12 @@
  * GNU General Public License for more details.
  */
 
+#include "debug.h"
 #include "edgetx.h"
+#include "os/sleep.h"
+#include "os/task.h"
+#include "os/time.h"
+#include "os/timer.h"
 #include "timers_driver.h"
 #include "hal/abnormal_reboot.h"
 #include "hal/watchdog_driver.h"
@@ -32,23 +37,23 @@
 #include "startup_shutdown.h"
 #endif
 
-RTOS_TASK_HANDLE menusTaskId;
-RTOS_DEFINE_STACK(menusTaskId, menusStack, MENUS_STACK_SIZE);
+task_handle_t menusTaskId;
+TASK_DEFINE_STACK(menusStack, MENUS_STACK_SIZE);
 
 #if defined(AUDIO)
-RTOS_TASK_HANDLE audioTaskId;
-RTOS_DEFINE_STACK(audioTaskId, audioStack, AUDIO_STACK_SIZE);
+task_handle_t audioTaskId;
+TASK_DEFINE_STACK(audioStack, AUDIO_STACK_SIZE);
 #endif
 
-RTOS_MUTEX_HANDLE audioMutex;
+mutex_handle_t audioMutex;
 
-#define MENU_TASK_PERIOD_TICKS         (50 / RTOS_MS_PER_TICK)    // 50ms
+#define MENU_TASK_PERIOD (50)  // 50ms
 
 #if defined(COLORLCD) && defined(CLI)
 bool perMainEnabled = true;
 #endif
 
-TASK_FUNCTION(menusTask)
+static void menusTask()
 {
 #if defined(LIBOPENUI)
   LvglWrapper::instance();
@@ -63,15 +68,14 @@ TASK_FUNCTION(menusTask)
     uint32_t pwr_check = pwrCheck();
     if (pwr_check == e_power_off) {
       break;
-    }
-    else if (pwr_check == e_power_press) {
-      RTOS_WAIT_TICKS(MENU_TASK_PERIOD_TICKS);
+    } else if (pwr_check == e_power_press) {
+      sleep_ms(MENU_TASK_PERIOD);
       continue;
     }
 #else
   while (pwrCheck() != e_power_off) {
 #endif
-    uint32_t start = (uint32_t)RTOS_GET_TIME();
+    time_point_t next_tick = time_point_now();
     DEBUG_TIMER_START(debugTimerPerMain);
 #if defined(COLORLCD) && defined(CLI)
     if (perMainEnabled) {
@@ -81,14 +85,8 @@ TASK_FUNCTION(menusTask)
     perMain();
 #endif
     DEBUG_TIMER_STOP(debugTimerPerMain);
-    // TODO remove completely massstorage from sky9x firmware
-    uint32_t runtime = ((uint32_t)RTOS_GET_TIME() - start);
-    // deduct the thread run-time from the wait, if run-time was more than
-    // desired period, then skip the wait all together
-    if (runtime < MENU_TASK_PERIOD_TICKS) {
-      RTOS_WAIT_TICKS(MENU_TASK_PERIOD_TICKS - runtime);
-    }
 
+    sleep_until(&next_tick, MENU_TASK_PERIOD);
     resetForcePowerOffRequest();
   }
 
@@ -99,24 +97,61 @@ TASK_FUNCTION(menusTask)
   drawSleepBitmap();
   edgeTxClose();
   boardOff();
+}
+
+static void audioTask()
+{
+  while (!audioQueue.started()) {
+    sleep_ms(1);
+  }
 
-  TASK_RETURN();
+#if defined(PCBX12S) || defined(RADIO_TX16S) || defined(RADIO_F16) || defined(RADIO_V16)
+  // The audio amp needs ~2s to start
+  sleep_ms(1000); // 1s
+#endif
+
+  time_point_t next_tick = time_point_now();
+  while (true) {
+    DEBUG_TIMER_SAMPLE(debugTimerAudioIterval);
+    DEBUG_TIMER_START(debugTimerAudioDuration);
+    audioQueue.wakeup();
+    DEBUG_TIMER_STOP(debugTimerAudioDuration);
+    sleep_until(&next_tick, 4);
+  }
+}
+
+static timer_handle_t _timer10ms = TIMER_INITIALIZER;
+
+static void _timer_10ms_cb(timer_handle_t* h)
+{
+  per10ms();
+}
+
+void timer10msStart()
+{
+  if (!timer_is_created(&_timer10ms)) {
+    timer_create(&_timer10ms, _timer_10ms_cb, "10ms", 10, true);
+  }
+
+  timer_start(&_timer10ms);
 }
 
 void tasksStart()
 {
-  RTOS_CREATE_MUTEX(audioMutex);
+  mutex_create(&audioMutex);
 
 #if defined(CLI) && !defined(SIMU)
   cliStart();
 #endif
 
-  RTOS_CREATE_TASK(menusTaskId, menusTask, "menus", menusStack,
-                   MENUS_STACK_SIZE, MENUS_TASK_PRIO);
+  timer10msStart();
 
-#if !defined(SIMU) && defined(AUDIO)
-  RTOS_CREATE_TASK(audioTaskId, audioTask, "audio", audioStack,
-                   AUDIO_STACK_SIZE, AUDIO_TASK_PRIO);
+  task_create(&menusTaskId, menusTask, "menus", menusStack, MENUS_STACK_SIZE,
+              MENUS_TASK_PRIO);
+
+#if defined(AUDIO)
+  task_create(&audioTaskId, audioTask, "audio", audioStack, AUDIO_STACK_SIZE,
+              AUDIO_TASK_PRIO);
 #endif
 
   RTOS_START();
diff --git a/radio/src/tasks.h b/radio/src/tasks.h
index 89f60156ddc..129abf7c78b 100644
--- a/radio/src/tasks.h
+++ b/radio/src/tasks.h
@@ -21,7 +21,7 @@
 
 #pragma once
 
-#include "rtos.h"
+#include "os/task.h"
 
 // stack sizes should be in multiples of 8 for better alignment
 #if defined (COLORLCD)
@@ -53,15 +53,14 @@
 #endif
 
 
-extern TaskStack<MENUS_STACK_SIZE> menusStack;
-extern TaskStack<MIXER_STACK_SIZE> mixerStack;
+extern task_handle_t menusTaskId;
 
 #if defined(AUDIO)
-extern TaskStack<AUDIO_STACK_SIZE> audioStack;
+extern task_handle_t audioTaskId;
 #endif
 
 #if defined(CLI)
-extern TaskStack<CLI_STACK_SIZE> cliStack;
+extern task_handle_t cliTaskId;
 #endif
 
 void tasksStart();
diff --git a/radio/src/tasks/mixer_task.cpp b/radio/src/tasks/mixer_task.cpp
index 921c92c7f6c..76b1cb89a8a 100644
--- a/radio/src/tasks/mixer_task.cpp
+++ b/radio/src/tasks/mixer_task.cpp
@@ -23,22 +23,25 @@
 #include "mixer_task.h"
 #include "mixer_scheduler.h"
 
+#include "os/task.h"
+
 #include "edgetx.h"
 #include "switches.h"
 #include "hal/usb_driver.h"
 
 #include "hal/watchdog_driver.h"
+
 #if defined(HALL_SYNC) && !defined(SIMU)
 #include "stm32_gpio.h"
 #include "hal/gpio.h"
 #endif
 
-RTOS_TASK_HANDLE mixerTaskId;
-RTOS_DEFINE_STACK(mixerTaskId, mixerStack, MIXER_STACK_SIZE);
+task_handle_t mixerTaskId;
+TASK_DEFINE_STACK(mixerStack, MIXER_STACK_SIZE);
 
 // mixer hold this mutex while computing
 // channels and sending them out
-static RTOS_MUTEX_HANDLE mixerMutex;
+static mutex_handle_t mixerMutex;
 
 // The mixer will start in 'paused' mode
 // and start working properly once
@@ -49,26 +52,26 @@ static bool _mixer_exit = false;
 
 void mixerTaskLock()
 {
-  RTOS_LOCK_MUTEX(mixerMutex);
+  mutex_lock(&mixerMutex);
 }
 
 // returns true if the lock could be acquired
 bool mixerTaskTryLock()
 {
-  return RTOS_TRYLOCK_MUTEX(mixerMutex);
+  return mutex_trylock(&mixerMutex);
 }
 
 void mixerTaskUnlock()
 {
-  RTOS_UNLOCK_MUTEX(mixerMutex);
+  mutex_unlock(&mixerMutex);
 }
 
 void mixerTaskInit()
 {
   mixerSchedulerInit();
-  RTOS_CREATE_MUTEX(mixerMutex);
-  RTOS_CREATE_TASK(mixerTaskId, mixerTask, "mixer", mixerStack,
-                   MIXER_STACK_SIZE, MIXER_TASK_PRIO);
+  mutex_create(&mixerMutex);
+  task_create(&mixerTaskId, mixerTask, "mixer", mixerStack, MIXER_STACK_SIZE,
+              MIXER_TASK_PRIO);
   mixerSchedulerStart();
 }
 
@@ -133,17 +136,9 @@ void execMixerFrequentActions()
 #if defined(BLUETOOTH)
   bluetooth.wakeup();
 #endif
-
-#if defined(SIMU)
-  if (_mixer_running) {
-    DEBUG_TIMER_START(debugTimerTelemetryWakeup);
-    telemetryWakeup();
-    DEBUG_TIMER_STOP(debugTimerTelemetryWakeup);
-  }
-#endif
 }
 
-TASK_FUNCTION(mixerTask)
+void mixerTask()
 {
 #if defined(IMU)
   gyroInit();
@@ -173,9 +168,8 @@ TASK_FUNCTION(mixerTask)
     mixerSchedulerEnableTrigger();
 
 #if defined(SIMU)
-    // TODO: should be using mixerTaskExit() instead...
     if (pwrCheck() == e_power_off) {
-      TASK_RETURN();
+      return;
     }
 #else
     // Emergency power OFF: in case the UI is not functional anymore
@@ -218,8 +212,6 @@ TASK_FUNCTION(mixerTask)
         maxMixerDuration = t0;
     }
   }
-
-  TASK_RETURN();
 }
 
 void doMixerCalculations()
diff --git a/radio/src/tasks/mixer_task.h b/radio/src/tasks/mixer_task.h
index 65c4e67b493..457b3591b9e 100644
--- a/radio/src/tasks/mixer_task.h
+++ b/radio/src/tasks/mixer_task.h
@@ -19,13 +19,13 @@
  * GNU General Public License for more details.
  */
 
-#include "rtos.h"
+#include "os/task.h"
 
 // needed by the mixer scheduler
-extern RTOS_TASK_HANDLE mixerTaskId;
+extern task_handle_t mixerTaskId;
 
 // function running the mixer task
-TASK_FUNCTION(mixerTask);
+void mixerTask();
 
 // init, create and start the OS task itself
 void mixerTaskInit();
diff --git a/radio/src/telemetry/hitec.cpp b/radio/src/telemetry/hitec.cpp
index b9b54deac69..a05681a5eef 100644
--- a/radio/src/telemetry/hitec.cpp
+++ b/radio/src/telemetry/hitec.cpp
@@ -20,6 +20,7 @@
  */
 
 #include "edgetx.h"
+#include "os/time.h"
 
 /* Full telemetry 
 packet[0] = TX RSSI value
@@ -354,7 +355,7 @@ void processHitecPacket(const uint8_t * packet)
       alt = (int16_t) ((packet[3] << 8) | packet[4]);
       sensor = getHitecSensor(HITEC_ID_ALT);
       setTelemetryValue(PROTOCOL_TELEMETRY_HITEC, HITEC_ID_ALT, 0, 0, alt, sensor->unit, sensor->precision);
-      current_ms = RTOS_GET_MS();
+      current_ms = time_get_ms();
       sensor = getHitecSensor(HITEC_ID_VARIO);
       value = (alt - last_alt) * 100;
       if ((current_ms - last_ms) < 1000)
diff --git a/radio/src/telemetry/telemetry.cpp b/radio/src/telemetry/telemetry.cpp
index c7c1f11b45e..c4019bd92e5 100644
--- a/radio/src/telemetry/telemetry.cpp
+++ b/radio/src/telemetry/telemetry.cpp
@@ -21,6 +21,8 @@
 
 #include "edgetx.h"
 #include "multi.h"
+#include "os/async.h"
+#include "os/timer.h"
 #include "pulses/afhds3.h"
 #include "pulses/flysky.h"
 #include "mixer_scheduler.h"
@@ -168,14 +170,10 @@ void telemetryMirrorSend(uint8_t data)
   }
 }
 
-#if !defined(SIMU)
-static TimerHandle_t telemetryTimer = nullptr;
-static StaticTimer_t telemetryTimerBuffer;
+static timer_handle_t telemetryTimer = TIMER_INITIALIZER;
 
-static void telemetryTimerCb(TimerHandle_t xTimer)
+static void telemetryTimerCb(timer_handle_t* h)
 {
-  (void)xTimer;
-
   DEBUG_TIMER_START(debugTimerTelemetryWakeup);
   telemetryWakeup();
   DEBUG_TIMER_STOP(debugTimerTelemetryWakeup);
@@ -183,25 +181,17 @@ static void telemetryTimerCb(TimerHandle_t xTimer)
 
 void telemetryStart()
 {
-  if (!telemetryTimer) {
-    telemetryTimer =
-        xTimerCreateStatic("Telem", 2 / RTOS_MS_PER_TICK, pdTRUE, (void*)0,
-                           telemetryTimerCb, &telemetryTimerBuffer);
+  if (!timer_is_created(&telemetryTimer)) {
+    timer_create(&telemetryTimer, telemetryTimerCb, "Telem", 2, true);
   }
 
-  if (telemetryTimer) {
-    if( xTimerStart( telemetryTimer, 0 ) != pdPASS ) {
-      /* The timer could not be set into the Active state. */
-    }
-  }
+  timer_start(&telemetryTimer);
 }
 
 void telemetryStop()
 {
-  if (telemetryTimer) {
-    if( xTimerStop( telemetryTimer, 5 / RTOS_MS_PER_TICK ) != pdPASS ) {
-      /* The timer could not be stopped. */
-    }
+  if (!timer_is_created(&telemetryTimer)) {
+    timer_stop(&telemetryTimer);
   }
 }
 
@@ -248,21 +238,8 @@ static void _poll_frame(void *pvParameter1, uint32_t ulParameter2)
 
 void telemetryFrameTrigger_ISR(uint8_t module, const etx_proto_driver_t* drv)
 {
-  BaseType_t xHigherPriorityTaskWoken = pdFALSE;
-  BaseType_t xReturn = pdFALSE;
-
-  if (!_poll_frame_queued[module] && xTaskGetSchedulerState() != taskSCHEDULER_NOT_STARTED) {
-    xReturn = xTimerPendFunctionCallFromISR(_poll_frame, (void*)drv, module, &xHigherPriorityTaskWoken);
-
-    if (xReturn == pdPASS) {
-      _poll_frame_queued[module] = true;
-    } else {
-      TRACE("xTimerPendFunctionCallFromISR() queue full");
-    }
-    portYIELD_FROM_ISR( xHigherPriorityTaskWoken );
-  }
+  async_call_isr(_poll_frame, &_poll_frame_queued[module], (void*)drv, module);
 }
-#endif
 
 inline bool isBadAntennaDetected()
 {