Hello everyone,
I am working on a custom board based on the STM32U575RGT6 (1MB Flash). I am encountering a hard fault (SecureFault) during the initialization of the Non-Secure application after integrating the SBSFU.
Context:
Hardware: Custom board with STM32U575RGT6.
Initial Project: A working application using TrustZone active + FreeRTOS (generated via CubeMX). The Option Bytes were set to a default 50/50 split (Secure/Non-Secure).
Goal: Implement a Secure Boot / Firmware Update mechanism.
What I did:
I used the ST example for B-U585I-IOT02A as a reference.
I integrated SBSFU_Boot and SBSFU_Loader into my project folder.
I adapted the linker scripts (.ld), postbuild.sh, and flash_layout.h to match the 1MB Flash size of the U575RGT6 (vs 2MB on the B-U585I).
In my original application, I replaced the .ld files and startup_xx.s files with those provided in the SBSFU_Appli example.
Configuration:
To simplify debugging, I disabled Tamper, Write Protection (WRP), and HDP protection in SBSFU_Boot.
RDP Level is set to Level 0.
The Behavior: The project compiles and links successfully. After flashing:
The Bootloader starts correctly.
It jumps to the Secure Application.
The Secure Application jumps to the Non-Secure Application.
Inside the Non-Secure main():
HAL_Init() executes fine.
HAL_PWREx_EnableVddA() executes fine.
CRASH: When calling SECURE_RegisterCallback(SECURE_FAULT_CB_ID, (void *)SecureFault_Callback);, the system jumps immediately to SecureFault_Handler().
Debugging Info: It seems related to the Non-Secure Callable (NSC) region or a GTZC configuration issue, but I am stuck. Since I adapted the flash layout for 1MB, I suspect I might have messed up a boundary definition.
Has anyone faced a similar issue when porting the U5 SBSFU to a smaller flash variant?
Any help or pointers on where to look would be greatly appreciated.
Thanks in advance!
