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BlueNRG-M2 bootloader with Flasher Utility v4.3 Auto Baudrate functionality failed


I have a BlueNRG-M2SP on a board with an STM32 Host. I assert the boot pin high and reset the M0 at the start to put it into Bootloader mode. I wait for the popup and set the baudrate, so far so good. When I issue a command with the Flasher Utility it fails with "Auto Baudrate functionality failed".

To see what was going on, I set up a serial port monitor and after the utility sent 0x7F to the client it responded with two bytes: 0xC0 0x79, not 0x79.

Then I reset the board and opened a serial terminal and sent 0x7F to the client, it responded with two bytes: 0xC0 0x79, not 0x79, same as with the utility.

I can successfully run all of the commands from the terminal and the command ACK is always 0x79, except for the ACK from the initial 0x7F. Looking at AN4872 it seems that the bootloader should be returning only 0x79 after receiving the 0x7F.

Based on some of the other questions and answers it seems as though going SWD might be less problematic. I would appreciate any suggestions/solutions for flashing the BLUENRG-M2 on a custom board.

Associate II

Hi, try to config a pull-up on the STM32 side for the STM32-USART-RX-line.