STM32N6 private key copy to another computer for binary signature

[nicoguilbaudsw]

Hi,

I follow the guideline on this page to integrate the binary signature for STM32N6: https://docs.zephyrproject.org/latest/boards/st/stm32n6570_dk/doc/index.html.

I'm using FSBL boot process (not MCU boot).

I suceed to flash and start several project, now i would like to migrate my project to another computer using the same board. When doing that the same project is not booting anymore. I think this is related to the signature key which is different on this other computer and the public key may be flashed to the STM32N6.

1- How to copy private key used for signature from computer 1 to computer 2 (where is located the private key) ?
2- How to reprogram a new public key in the STM32N6 ?

Best Regards,

[brendena]

I'm sorry i don't know the answer for you, but i can if you some info.

Here is where for the N6 they set all the programming values.

• https://github.com/zephyrproject-rtos/zephyr/blob/main/boards/st/stm32n6570_dk/board.cmake

But i'm not sure you need to copy a private key. By default there is no key. You can see that in your signing tool

       -------------------------------------------------------------------
                       STM32 Signing Tool v2.22.0                     
       -------------------------------------------------------------------

[Header v2.3] Align the payload to the 0x400 offset by adding padding bytes at the beginning of the payload.
Adding head padding bytes for payload with header v2.3
 Header version 2.3 preparation... 
Extracting Entry point value from the input file...
Entry point value : 0x341828a1
 The headred image file generated successfully:  

Header description:

    Magic: 0x53544d32
    Signature: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 
               00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 
               00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 
    Checksum: 0x53f18e
    Header version: 0x20300
    Size: 0xd1a0
    Load address: 0xffffffff
    Entry point: 0x341828a1
    Image version: 0x0
    Extension: 0x80000000
 

All those zero's should be your key and by default there all 0's

[nicoguilbaudsw]

thanks, probably my environment migration is coming from another issue...