How to unlock PCROP protection locked by SBSFU on STM32H753

[James Shih]

Hi,

I'm running the project which is evaluating the SBSFU for the secure firmware upgrade, I have no problem to run SBSFU 2_Images example on Nucleo-H753ZI and execute the secure firmware upgrade, but one thing bug me is the way to unlock the chip.

After the evaluation, I used ST-Link with STM32CubeProgrammer to unlock the Read Out Protection, but somehow can't re-program properly then figured out the root cause is the PCROP Protection in AREA1 is still locked.

I reviewed the manual at

https://www.st.com/resource/en/reference_manual/dm00314099-stm32h742-stm32h743-753-and-stm32h750-value-line-advanced-arm-based-32-bit-mcus-stmicroelectronics.pdf

followed the instruction of "Flash bank erase with automatic protection-removal sequence" at page 166, to unlock the PCROP, sometimes I can unlock it right away, but sometimes I have to do the same procedure couple and/or many times to unlock it.

Is there any other proper way to unlock the PCROP?

Thanks.

James Shih

[Jocelyn RICARD]

Hello James,

normally you just need to remove PCROP while doing RDP regression.

Could you check with last version of STM32CubeProgrammer and use

STM32_Programmer_CLI.exe -c port=swd mode=UR -ob PROT_AREA_START1=0xFF PROT_AREA_END1=0 RDP=0xAA

Best regards

Jocelyn