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Visitor II
December 22, 2025
Question

A custom bootloader is working on stm32h745i-Discovery but not in a custom board

  • December 22, 2025
  • 3 replies
  • 105 views

Hi,

I am Working on STM32H745XIH6 MCU which embed in our custom board. I have bootloader code which is working fine on STM32H745I-Discovery board. But when I use bootloader in out custom board problem is unable to jump on application code, but same thing is working fine with STM32H745I-Discovery with same bootloader code and application code.

I have debug more and got same interesting things happen which mention in below

  • When I flash the application code from STMcubeProgrammer into my custom board and then give power cycle that time jump from bootloader to application code is working fine.
  • When I flash the application code from bootloader into my custom board, that time I will face the issue in jump from bootloader to application code.
  • Then I have check the Flash memory section of application code and compare in both scenario when flash through bootloader or flash through STM32CudeProgrammer. Application code is match properly. So writing into flash memory through bootloader code is working fine.

    Can any please suggest me what exactly happen in my case and what I need to do for fix the issue.

    Thanks 
    Vineet

 

    This topic has been closed for replies.

    3 replies

    Technical Moderator
    December 22, 2025

    Hello,

    First, you need to confirm you have the exact replication of Stm32h745i-Discovery hardware on your custom board. Do you confirm that?

    Visitor II
    December 22, 2025

    Hi,

    Thanks for response,

    Hi have checked with hardware person acknowledge that STM32H745I-Dicovery board and custom board hardware is same.

    Can you please suggest me the solution what I can do in software side.

    Thanks 
    Vineet

    Super User
    December 22, 2025

    > same thing is working fine with STM32H745I-Discovery with same bootloader code and application code.

    > STM32H745I-Dicovery board and custom board hardware is same

    Let's be objective here:

    If the hardware is the same, the software will work the same.

    Visitor II
    January 5, 2026

    Hi,

    I got the issue in my bootloader code, we can write minimum 32 byte of data into flash and lower then 32 byte of data making issue.
    So I have compare my data after flashing through bootloader with actual .bin file got to know last some byte not written properly. 

    I just make small change in my code if last block of data is less than 32 byte file rest of bytes with 0xFF. after this my bootloader is working fine.

    thanks all for the response, I really appreciated.