STM32F401CC bootloader problem

[hexfet13 e]

Posted on June 28, 2017 at 14:27

Hi all,

i have two custom board with a microcontroller STM32F401CC in a 48pin package. One of these two micro is not working anymore due to a programmed option byte during a debug session. ST-link tell me this micro has a 'read out protection' set to level 1 instead level 0.

I tried to restore the level 0 with ST-link utility, but it can't restore the original stete to level 0(STlink gives me the correct id and microcontroller number)

So, i'm trying to restore this microcontroller with the utility Flash Loader Demonstrator, using the UART1 ( pins: boot0=HIGH, boot1=LOW) using an  usb-serial adapter with this parameter 9600-8-EVEN btu i receive always the same reply:

Unrecognized device... Please, reset your device then try again.

I tried to use the serial bootloader with the second board (this is 100% working) and i have always the same reply:

does anyone can tell me how to solve this problem?

Thanks!

[Tesla DeLorean]

Posted on June 28, 2017 at 17:45

Can't say I have boards with these chips. I have F401RET6 parts, on a third party board where they locked their firmware, I removed this using USB DfuSe as the board lacked a serial port.

You could use something like RealTerm to send hex bytes to the board, initially an 0x7F pattern and confirming you see a 0x79 response.

Sending 0x01,0xFE should illicit a multi-byte response, 0x02,0xFD should report the chip id

On the F1 0x92,0x6D Disabled Readout protection, you'd need to review the protocol manual for the F4 command set.

Attach the interaction where you send the training byte, and first two commands listed.

[Anil3]

Hi @hexfet13 e 

I am trying to implement custom bootloader for the same controller (STM32F401CCU6) as i am new to bootloader i am struggling with the concepts and the way of implemetation. if you don't mind could you please share me your bootloader code for me as it is working for you will try to take it as referance for me and customise it for my code.

Awaiting for your valuable reply,

Thank you!

regards,

ANIL.