STM32F105: same firmware loaded to two devices but the one of them is not working as expected

[Einar]

Hello,

I read out bin file from MCU STM32F105 and tried to write to the same new MCU, but on new MCU firmware do not work correctly.

Different is between those mcu the old have marked CHN GQ and new one have MYS 99

Any ideas where is the problem?

[SofLit]

Hello,

It could be something related to the option bytes.

[Andrew Neil]

I don't know the STM32 behaviour if you read a locked chip - does the read just fail? Or does the read proceed, but give rubbish data?

Also, perhaps the owner of the code has done something "clever" to prevent copying; eg, keying to the unique ID?

[SofLit]

Did you retrieve the all Flash content?

As it could be something related to the option bytes (different values). You can check and compare the content of the option bytes using STM32CubeProgrammer tool going to OB menu:

[Tesla DeLorean]

Perhaps review in the context of the rest of the circuit.

Does the external clock start? Any signs of life?

BOOT0 pulled LOW?

Perhaps review the code, check if that's got the potential to work properly, or has some secondary dependencies.

[Einar]

Chip is not locked, and firmware is working but partially, indicator is blinking, but MODE button do not work.

[Einar]

Old chip is damaged, one pin is broken I have resoldered new chip to old pcb, so problem can be only with new chip or firmware.