X-CUBE-AWS demo project on B-L4S5I-IOT01A does not run

[Nick Faughey]

I'm trying to run the aws_demos project from X-CUBE-AWS on the B-L4S5I-IOT01A development board. I've successfully programmed and run the provisioning image. I've successfully built the aws_demos project, and have the "B-L4S5I-IOT01_aws_demos.sfb" and "SBSFU_B-L4S5I-IOT01_aws_demos.bin" binaries in the STM32CubeIDE/PostBuild folder. When I program and run the latter program as instructed in the "Getting Started with X-CUBE-AWS" manual though, it seems the program hangs and gets rebooted by the watchdog, instead of outputting the PEM certificate.

======================================================================
=              (C) COPYRIGHT 2017 STMicroelectronics                 =
=                                                                    =
=              Secure Boot and Secure Firmware Update                =
======================================================================
 
 
= [SBOOT] SECURE ENGINE INITIALIZATION SUCCESSFUL
= [SBOOT] STATE: CHECK STATUS ON RESET
.  WARNING: A Reboot has been triggered by a Watchdog reset!
.  Consecutive Boot on error counter = 8 
.  INFO: Last execution detected error was:Watchdog error.
= [EXCPT] WATCHDOG RESET FAULT!
= [SBOOT] STATE: CHECK NEW FIRMWARE TO DOWNLOAD
= [SBOOT] STATE: CHECK KMS BLOB TO INSTALL
= [SBOOT] STATE: CHECK USER FW STATUS
= [SBOOT] LOADING CERTS FROM SECURE ENGINEOK
 
= [SBOOT] Verifying the Certificate chain... OK
 
= [SBOOT] Verify Header Signature... OK
.  A valid FW is installed in the active slot - version: 1
= [SBOOT] STATE: VERIFY USER FW SIGNATURE
= [SBOOT] CHECKING IMAGE STATE
=         SFU_IMG_CheckImageState Image State = 1
= [SBOOT] IMAGE STATE OK
= [SBOOT] STATE: EXECUTE USER FIRMWARE
= [SBOOT] System Security Check successfully passed. Starting...
= [FWIMG] Slot #0 @: 8105000 / Slot #1 @: 8036000 / Swap @: 81d5000
 
 
======================================================================
=              (C) COPYRIGHT 2017 STMicroelectronics                 =
=                                                                    =
=              Secure Boot and Secure Firmware Update                =
======================================================================
 
 
= [SBOOT] SECURE ENGINE INITIALIZATION SUCCESSFUL
= [SBOOT] STATE: CHECK STATUS ON RESET
.  WARNING: A Reboot has been triggered by a Watchdog reset!
.  Consecutive Boot on error counter = 9 
.  INFO: Last execution detected error was:Watchdog error.

I haven't changed any of the aws_demos source code. Any ideas or further troubleshooting?

[NorfLoud]

This is normal for ST. Try disabling watchdog timer or moving its launch to the end of the peripheral initialization list. Check whether the watchdog timer value update function is available.

[Nick Faughey]

The watchdog reset here is just a symptom of the issue - disabling the watchdog still makes the program hang. Adding a configPRINTF() just after initializing UART in the main() function confirms that the application is at least not making it to there, as there's no serial output from the main application, it just hangs after the bootloader says it's executing user firmware.

[Nick Faughey · Accepted solution]

It turns out that a full chip erase via STM32CubeProgrammer, followed by a hard boot (power unplugged), followed by reflashing the application, resolves this for both of my units. I haven't been able to reproduce - perhaps something setting was shipped out of sync from the factory and the chip erase caught it. I'll update when I get more of these units if I run into the issue again.