From 9ca33ea611588ac0e58031777d2916db7831513e Mon Sep 17 00:00:00 2001
From: Mikey Sklar <mikeysklar@gmail.com>
Date: Mon, 26 May 2025 17:37:24 -0700
Subject: [PATCH] macos support for msc

Changing from multi-block writes to single block worked for macos and ubuntu. I was able to mount read and write both flash and microSD using a Metro RP2040.
---
 examples/MassStorage/.DS_Store                | Bin 0 -> 6148 bytes
 .../msc_external_flash_sdcard.ino             |  34 ++++++++++--------
 2 files changed, 19 insertions(+), 15 deletions(-)
 create mode 100644 examples/MassStorage/.DS_Store

diff --git a/examples/MassStorage/.DS_Store b/examples/MassStorage/.DS_Store
new file mode 100644
index 0000000000000000000000000000000000000000..fa38b7ff3d5beb77973a053c761c9b73d678d478
GIT binary patch
literal 6148
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zG_P2%0m$m3y#tm27F0!isTqr&tB&L<JVK<h#v@L6r#+w>MNd04_ZF`>Vu$S@zrmiK
zC)$RmFI*qdGOA(q_H%RS_HW&@-#lG9y~#i_kPIXP$v`qN!GQK&%HrBFZ8DGyBm-v#
z^!re#iZ!rzv`+_(jR3?s-6mYyEI};lAlAU%ksgY8D$!FVMhx+E`b)&sz~0f*Au)VN
z+$=Gnh~3Wm#lj)gF>NxC3=A2V`F5%O|DO8G{69>}T{4gi{3`}zzTT`?d{Xq*(c`q&
v7U~1_M;L42G}elV){42&R(x|2S9Hzu8rVBpI{lVT%pU>eB_$d73kJRcMSL3?

literal 0
HcmV?d00001

diff --git a/examples/MassStorage/msc_external_flash_sdcard/msc_external_flash_sdcard.ino b/examples/MassStorage/msc_external_flash_sdcard/msc_external_flash_sdcard.ino
index 4b7b6e15..9f24edf0 100644
--- a/examples/MassStorage/msc_external_flash_sdcard/msc_external_flash_sdcard.ino
+++ b/examples/MassStorage/msc_external_flash_sdcard/msc_external_flash_sdcard.ino
@@ -214,15 +214,17 @@ void loop() {
 // SD Card callbacks
 //--------------------------------------------------------------------+
 
-int32_t sdcard_read_cb (uint32_t lba, void* buffer, uint32_t bufsize)
-{
-  bool rc;
-
-#if SD_FAT_VERSION >= 20000
-  rc = sd.card()->readSectors(lba, (uint8_t*) buffer, bufsize/512);
-#else
-  rc = sd.card()->readBlocks(lba, (uint8_t*) buffer, bufsize/512);
-#endif
+int32_t sdcard_read_cb (uint32_t lba, void* buffer, uint32_t bufsize) {
+  bool rc = true;
+  uint8_t* buf = (uint8_t*)buffer;
+
+  // Perform each sector with a single-block CMD17
+  for (uint32_t i = 0; i < bufsize/512; i++) {
+    if (!sd.card()->readBlock(lba + i, buf + i*512)) {
+      rc = false;
+      break;
+    }
+  }
 
   return rc ? bufsize : -1;
 }
@@ -231,17 +233,19 @@ int32_t sdcard_read_cb (uint32_t lba, void* buffer, uint32_t bufsize)
 // Process data in buffer to disk's storage and 
 // return number of written bytes (must be multiple of block size)
 int32_t sdcard_write_cb (uint32_t lba, uint8_t* buffer, uint32_t bufsize) {
-  bool rc;
+  bool rc = true;
 
 #ifdef LED_BUILTIN
   digitalWrite(LED_BUILTIN, HIGH);
 #endif
 
-#if SD_FAT_VERSION >= 20000
-  rc = sd.card()->writeSectors(lba, buffer, bufsize/512);
-#else
-  rc = sd.card()->writeBlocks(lba, buffer, bufsize/512);
-#endif
+  // Perform each 512-byte sector as a single-block CMD24
+  for (uint32_t i = 0; i < bufsize/512; i++) {
+    if (!sd.card()->writeBlock(lba + i, buffer + i*512)) {
+      rc = false;
+      break;
+    }
+  }
 
   return rc ? bufsize : -1;
 }