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Processor locked? How to reset Option Bytes in STM32H7 proccessor?

Yuri Andrade Rodrigues
Associate II

Hello,

I have been working with the STM32H7 and I have been implementing the Protected Area for saving memory in the sector 1 (128KB) shared with my boot loader and the application.

I have experienced two different issues with this H7 processor:

  1. When I enable the PCROP and changed the RDP from level 1 to level 0 (as described in RM0433 at page 159-160), it would cause a mass erase and remove the protection area. Correct? It locked my processor. The memory is still protected, I cannot write and read from there and even use this processor no more.
  2. When I followed the steps to do a bank erase with protection removal, it removed from bank 2, however, it locked as the same as item 1 for the other bank. I as running on bank 1 when I did this protection removal. Without this protection I could erase the whole bank causing just a debugger crash, not locking the processor.

My question are:

  1. I see in downloads tab for the STM32H7 there is the FLASHER-STM32 available. Unfortunately, it does not work the this H7 core. Days ago we have got it working with our serial programmer and we found out the problem was an extra byte in the first communication. Will STM fix this FLASHER-STM32 for the H7 processor? Could this program recover the option bytes?
  2. Is the same bootloader protocol for STM32H7 than the others? As the H7 has bootloader V13.2 and the F7, for example, has V9.0. I don't see H7 processor listed in AN3155 document. Are the bootloaders similar or they have an different protocol with extra functions?
  3. I use a Jlink Segger to reset the option bytes from processors as STM32F4 and STM32F7. Unfortunately, they do not have the processor STM32H7 listed. Do you know how long will it take to get supported? Does the STM have any program with could through Jlink could connect to the processor and reset the processor to the manufacture setting?

0690X000006BvihQAC.png

I have tried through the embedded bootloader rewrite the option bytes, but it seems not working.

Best Regards.

Yuri Rodrigues

1 REPLY 1
dominicc
Associate II

I was in a situation where I needed to remove an PCROP today. The procedure is detailed in the Reference Manual (RM0433 Rev 5), "3.3.10 - Flash bank erase with automatic protection-removal sequence". See "Flash bank erase with automatic protection-removal sequence".

It worked for me.