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Associate
February 26, 2025
Solved

STM32CubeProg stm32h7xx Option Bytes User Configuration disappears if disabled by firmware

  • February 26, 2025
  • 6 replies
  • 2343 views

If on a STM32H747 the Cortex-M4 (BCM4 or BOOT_M4 Bit) is disabled by software, it is impossible to reactivate it with the STM32CubeProg v2.18.0 because the checkbox disappears in the user interface. But this happens only if you do a power cycle and reconnect to the target.

Best answer by mƎALLEm

So it's a GUI issue not related to the hardware.

Internal ticket 204208 has been opened for analysis. This ticket is not accessible by the community users.

 

6 replies

TDK
Super User
February 27, 2025

Unable to replicate this on a STM32H745.

What happens if you clear it using STM32CubeProgrammer instead of firmware?

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dariisAuthor
Associate
February 27, 2025

It happens with STM32CubeProg too:

reproduce_missing_BCM4.png

mƎALLEm
Technical Moderator
February 27, 2025

Hello,

I was not able to reproduce the behavior with CubeProgrammer V2.18:

mALLEm_0-1740661920721.png

- Connected to the H745 Disco board (ested also with H747 Disco board)

- Disable BCM4 in the option bytes

- Disconnect the USB cable (power cycle)

- Reconnect USB + connect with CubeProgrammer

- In the option bytes BCM4 still available.

 

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mƎALLEm
Technical Moderator
February 27, 2025

What is your platform/OS?

Is that possible to uninstall and reinstall CubeProgrammer and see what happens?

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dariisAuthor
Associate
February 27, 2025

Fair enough, I do not have the problem with the H747 disco board (but I did not test to write the OB by SW).

I use a custom HW and a J-Link with Linux Debian, I tried reinstall CubeProgrammer but it did not help.

So I think we keep it as it is.

mƎALLEm
Technical Moderator
February 27, 2025

Hello,

After applying the the new option byte configuration go to the device memory and read the content of the registers

FLASH_OPTSR_CUR and FLASH_OPTSR_PRG:

FLASH_OPTSR_CUR located at the address 0x5200201C 

FLASH_OPTSR_PRG located at the address 0x52002020 

mALLEm_1-1740674871397.png

For example this is a screenshot of my FLASH_OPTSR_CUR reading:

mALLEm_2-1740674955363.png

8 means the CM4 is disabled. C means CM4 is enabled.

If you find that the reading of these registers corresponds to what you set in the option bytes, this means the option byte were physically correctly set and there is something went wrong in CubeProgrammer.

 

 

 

 

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mƎALLEm
mƎALLEmBest answer
Technical Moderator
February 28, 2025

So it's a GUI issue not related to the hardware.

Internal ticket 204208 has been opened for analysis. This ticket is not accessible by the community users.

 

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mƎALLEm
Technical Moderator
March 5, 2025

Behavior reproduced internally by our teams. 

It will be analyzed asap. 

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Explorer
May 6, 2025

Any update on this?  I have the exact same issue.  I unchecked BCM4 in STM32CubeProgrammer for STM32H745, and then after reboot, the checkbox isn't even there to check it again.

Also, it is not just GUI because the Cube Programmer CLI says the BCM4 register isn't available now.

mƎALLEm
Technical Moderator
May 6, 2025

If there were any update I've already provided it..

Don't expect to have an updated version very soon. I will keep you informed for any update.

Thank you for your understanding.

 

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Aziz BRIGUI
Technical Moderator
November 17, 2025

Hello @dariis

Issue fixed in the latest STM32CubeProgrammer release available under this link: STM32CubeProg | Software - STMicroelectronics.

Aziz

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