Context management restores soft-se root keys?

[brocaar]

It looks like when CONTEXT_MANAGEMENT_ENABLED is enabled, together with the soft-se option, that changing the keys in se-identity.h has no effect. I noticed this after updating the LORAWAN_JOIN_EUI and NWK_KEY. After (re)flashing, the device kept using the old LORAWAN_JOIN_EUI (and I assume as well the NWK_KEY, as the device failed to join).

I tried removing the build folder, make clean etc... but none of my changes had any effect. Then I noticed the ###### =========== CTXS RESTORED =========== ###### message. After disabling CONTEXT_MANAGEMENT_ENABLED, rebuild and reflash, the device succesfully joined using the new LORAWAN_JOIN_EUI and NWK_KEY.

[mluis1]

A few questions:

• Which version are you using?
• Which platform?
• Have you tried to make a mass-erase of the MCU Flash memory?
  The NVM data memory doesn't not get erased by updating the firmware.

If you are using a version newer or equal to v4.4.7 (LoRaWAN 1.0.3), v.4.5.1 (LoRaWAN 1.0.4) or master (1.0.4)/develop(1.0.4/1.1.1) branch you have the possibility to erase the NVM data through the serial interface by pressing ESC then shift N keys.

[mluis1]

If you don't mind I move this issue to the Discussions tab.

[brocaar]

Version: d02b2f8
Platform: B-L072Z-LRWAN1

I can still reproduce this:

1. I create a firmware with DevEUI / JoinEUI / AppKey A
2. I flash A to the device
3. I let the device join
4. Device joins with A
5. I create a new firmware with DevEUI / JoinEUI / AppKey B
6. I flash B to the device
7. I power-cycle the device
8. Device joins with A
9. I power-cycle the device
10. Device joins with A
11. ....
12. ESC & shift+N + power-cycle
13. Device joins with B

[brocaar]

These are the local changes that I have made:

$ git diff
diff --git a/src/apps/LoRaMac/periodic-uplink-lpp/B-L072Z-LRWAN1/main.c b/src/apps/LoRaMac/periodic-uplink-lpp/B-L072Z-LRWAN1/main.c
index 89bb63bd..031090c4 100644
--- a/src/apps/LoRaMac/periodic-uplink-lpp/B-L072Z-LRWAN1/main.c
+++ b/src/apps/LoRaMac/periodic-uplink-lpp/B-L072Z-LRWAN1/main.c
@@ -73,7 +73,7 @@
  *
  * \remark Please note that LORAWAN_DEFAULT_DATARATE is used only when ADR is disabled 
  */
-#define LORAWAN_DEFAULT_DATARATE                    DR_0
+#define LORAWAN_DEFAULT_DATARATE                    DR_5
 
 /*!
  * LoRaWAN confirmed messages
diff --git a/src/peripherals/soft-se/se-identity.h b/src/peripherals/soft-se/se-identity.h
index 872167b4..c9abc932 100644
--- a/src/peripherals/soft-se/se-identity.h
+++ b/src/peripherals/soft-se/se-identity.h
@@ -66,17 +66,17 @@ extern "C" {
  * When set to 1 DevEui is LORAWAN_DEVICE_EUI
  * When set to 0 DevEui is automatically set with a value provided by MCU platform
  */
-#define STATIC_DEVICE_EUI                                  0
+#define STATIC_DEVICE_EUI                                  1
 
 /*!
  * end-device IEEE EUI (big endian)
  */
-#define LORAWAN_DEVICE_EUI                                 { 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00 }
+#define LORAWAN_DEVICE_EUI                                 { 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x04 }
 
 /*!
  * App/Join server IEEE EUI (big endian)
  */
-#define LORAWAN_JOIN_EUI                                   { 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00 }
+#define LORAWAN_JOIN_EUI                                   { 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x04 }
 
 /*!
  * Secure-element pin
@@ -112,8 +112,8 @@ extern "C" {
              * WARNING: FOR 1.0.x DEVICES IT IS THE \ref LORAWAN_APP_KEY                                            \
              */                                                                                                     \
             .KeyID    = NWK_KEY,                                                                                    \
-            .KeyValue = { 0x2B, 0x7E, 0x15, 0x16, 0x28, 0xAE, 0xD2, 0xA6, 0xAB, 0xF7, 0x15, 0x88, 0x09, 0xCF, 0x4F, \
-                          0x3C },                                                                                   \
+            .KeyValue = { 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, \
+                          0x04 },                                                                                   \
         },                                                                                                          \
         {                                                                                                           \
             /*!

[MedadRufus]

Only ESC & shift+N + power-cycle will wipe the old context data from the EEPROM. So if you want to change the soft-se keys, flash the new keys, then run ESC & shift+N + power-cycle.

[mluis1]

@brocaar

As said by @MedadRufus in your step list once you have executed step 12 the end-device erases the EEPROM data and then at step 13 it uses your new keys.

The EEPROM data is only erased once the MCU has received the ESC + N sequence. Then by reseting/power cycling the MCU it will notice that the EEPROM data is no more valid which makes the end-device to re-initialize everything.

LoRaMac-node/src/apps/LoRaMac/common/LmHandler/LmHandler.c

Lines 256 to 269 in d02b2f8

	// Restore data if required
	nbNvmData = NvmDataMgmtRestore( );
	// Try to restore from NVM and query the mac if possible.
	if( nbNvmData > 0 )
	{
	LmHandlerCallbacks->OnNvmDataChange( LORAMAC_HANDLER_NVM_RESTORE, nbNvmData );
	}
	else
	{
	// Configure the default datarate
	mibReq.Type = MIB_CHANNELS_DEFAULT_DATARATE;
	mibReq.Param.ChannelsDefaultDatarate = LmHandlerParams->TxDatarate;
	LoRaMacMibSetRequestConfirm( &mibReq );

If nbNvmData is greater than 0 the firmware restores the EEPROM data. In case nbNvmData equals 0 the firmware initializes everything.

[brocaar]

Maybe this (ESC & + n) is something to add to the documentation? (https://github.com/Lora-net/LoRaMac-node/blob/master/README.md#soft-se)

In order to update the end-device identity (DevEUI, JoinEUI and AES128 keys) one must update the se-identity.h file located under ./src/peripherals/soft-se/ directory.

That is what I did and not being aware that this state is not only stored inside the firmware binary but also persisted somewhere else in memory, it took me quite some time to figure out what was going on.

[mluis1]

You are right @brocaar.
We did not had the time yet to update the documentation.
The non-volatile storage is pretty new (introduced with LoRaWAN 1.0.4 implementation) and users could use either MCU internal memory or an external non volatile memory.

[mluis1]

I have added a new chapter to the README.md file describing how to reset the NVM contents.
Serial console NVM management

[MedadRufus]

I just got caught by this requirement again today!

[shabaz-git]

Hi,
The same problem I am also facing. I am using fit iot-lab hardware (b-l072z-lrwan1 module).

When I observed this behavior I tried with erasing the NVM in the start of the application using NvmDataMgmtFactoryReset() .
But this led into a late join response because of the DevNonce restriction. Is there any thing other than this, we can do to flash new eui's to same hardware.

To solve this can't we take a decision about the restoring the nvm data after comparing it with the data provided in the "se-identity.h" .
Is such implementation is already there?If this is not possible or not a good option, why?

Is there any way I can pass ESC + N.

My project is having a continuous power supply and for this I want to store the data in NVM only when I intended to power off the node. Is there any way to achieve this?

[bwesen]

I couldn't get soft-se to work either (latest stack). It seems there is a problem in the LmHandlerInit code, it first calls LoRaMacInitialization which does a wipe of the soft-se NVM, then it proceeds to

    mibReq.Type = MIB_JOIN_EUI;
    LoRaMacMibGetRequestConfirm( &mibReq );
    memcpy1( CommissioningParams.JoinEui, mibReq.Param.JoinEui, 8 );

which, of course, then reads out 0's and puts in CommissioningParams.JoinEui no matter what.

What I really wanted to do was to use SecureElementSetJoinEui(eui); to setup the Join EUI before LmHandlerInit but that won't work as that function re-initializes the soft-se module and wipes whatever you wrote there first.

I ended up having to monkeypatch a callback inside LmHandlerInit into my main code, which does the SetJoinEui there...