NUCLEO-F446RE “The interface firmware FAILED to reset/halt the target MCU"

[hudakz (Zoltan Hudak)]

I had a similar error message reported in the FAIL.TXT file located on the board’s virtual disk after I accidentally interrupted an ongoing program download to the chip:

The interface firmware FAILED to initialize the target MCU.

In addition, the chip got locked (I was not able to connect to it anymore) as reported above by David.

Performing the following steps fixed the issue:

• Install the STM32CubeProgrammer to your host PC.
• Launch the STM32CubeProgrammer and in the ST-LINK configuration window click on the refresh Serial number button (see in the picture below).
• In the ST-LINK configuration window reduce the Frequency from 4000 to 1800 (see in the picture below).
• In the ST-LINK configuration window change the Mode to Under reset (see in the picture below).

• On the target board push the RESET button and, while holding down the RESET button, click on the Connect button in the STM32CubeProgrammer (see in the picture above).

• Release the RESET button on the target board.

• Once the chip is connected, initialize a Full chip erase by clicking on the button.

• Check/modify the Option bytes as needed by clicking on the button.

• Open the file containing the binary code and then download it to the chip.