STM32F469N - Cannot program option bytes, cannot erase flash.

[JVan .3]

I've got a custom board with an STM32F469, 32 Mbit of parallel flash, and 64 Mbit of external DRAM. This board had been working fine until an incident where execution or data fetch occurred on the external 32 MBit flash, which had not been programmed. After this happened, the device was unable to be debugged.

Further investigation using the STM32Cube programmer revealed that full chip erase won't work. Trying this results in the error "Error: Mass erase operation failed. Please verify flash protection."

Trying to change the value of the nWRPx bits is unsuccessful.

I also noted that the read out protection value is invalid (0) and cannot be set to the correct value (AA) when I try, I get Error: Option Byte Programming failed.

Any ideas about how to proceed here? I'm using an STLink-V3SET, though I have segger tools available too.

Josh

[Imen.D]

Hello @JVan .3​ and welcome to the Community :)

Try to strap BOOT0 high and connect to the board in normal mode.

Maybe this post will help you in your issue.

Please let me know if this solved your issue.

Imen