How to Debug Cortex-M33 Standalone on STM32MP257F-EV1 Without Booting Linux?

[S_KUMAR]

 

Hi,

I am working with the STM32MP257F-EV1 board and would like to debug the Cortex-M33 core using the debugger using ST-LINK.

Currently, I am unable to debug the Cortex-M33 core directly and I receive an error during the debug connection. I have attached a screenshot of the debug error for reference.

I noticed the following behavior:

• If I boot the Cortex-A35 core from the SD card and allow Linux to complete its boot process, I can then successfully debug the Cortex-M33 core.

• However, if I do not boot Linux on the A35 core, I am unable to connect to/debug the M33 core.

I would like to know whether the Cortex-M33 on the STM32MP257F-EV1 can be debugged standalone, without booting the Cortex-A35/Linux, similar to debugging the Cortex-M4/M7 on a conventional STM32 MCU such as the STM32H745XI-DISCO.

Specifically:

1. Is booting Linux on the Cortex-A35 mandatory before the Cortex-M33 can be debugged?

2. Is there a way to debug the Cortex-M33 standalone immediately after reset/power-up, without booting the A35/Linux?

3. If standalone debugging is possible, what is the recommended boot/debug sequence and debugger configuration?

4. Are there any STM32MP25 reference manuals, application notes, examples, or STM32CubeIDE/debugger configuration guides that explain how to debug the Cortex-M33 independently, similar to a normal STM32 MCU?

Any guidance or relevant documentation would be greatly appreciated.

Thank you.