[WEACT_STM32F411CEU6] unable to re-flash firmware

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[WEACT_STM32F411CEU6] unable to re-flash firmware

Post by RobH » Sat Aug 01, 2020 8:30 am

A few days ago I received my black-pill and I succeeded to build and flash Micropython V1.12-623 (without any extra flash), mem_free() shows 97600. I mounted external flash (on a separate board with M25Q128 connected as described in Readme.md), modified the mpconfigboard.h file as indicated and re-built the firmware.
However I cannot get the board in the proper state for dfu-util or pydfu.py anymore. Both report that they cannot find a DFU device.
The boot-reset button sequence seems not to have the desired effect. Importing pyb.bootloader is impossible: a terminal session shows heavy error reporting (in a loop?) which seems uninterruptible by a Ctrl-C or Ctrl-D (when A9 and A10 are connected before power-up).
What can I do?

[addition aug 2]
Discovered a method to get the board in bootloader mode:
- disconnect USB
- connect pins A9-A10
- connect USB
- start a terminal session
- remove connection between A9-A10 (this terminates the error reporting)
- import pyb;pyb.bootloader()
Now the firmware can be refreshed!

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