My Experience with STM32's Native DFU Bootloader

In my experience, I have found this to be frequently unreliable and inconsistent/indiscernable behaviour considering computer, operating system, or particular board used.

I see the QMK Documentation page on the Blackpill[5] explains that this has to with its 25MHz crystal; and because my MiniF4-36 design uses the pin A10 without an external pull-up resistor.

Not even "hold the boot button for 2 minutes[4]" was enough to help.

Ultimately, I think having an ST-Link device is necessary to at least flash an easier to use bootloader onto the board.

Bootloaders QMK Docs Recommend

In the QMK Docs, "Using QMK" -> "Guides" -> "Flashing" -> "Flashing"[0], the following bootloaders are suggested:

• For STM32F4 (e.g. the WeAct Studio MiniF4 "Black pill" boards):

• Adafruit's tinyuf2[1].

  • QMK will generate a .uf2 firmware file if the rules.mk is configured correctly.

• For STM32F103 (e.g. the "blue pill" boards):

• rogerclarkmelbourne/STM32duino-bootloader[2].

  • With QMK, and the rules.mk set to use this bootloader, (e.g. as handwired/onekey/bluepill has by default), the complied .bin won't work if flashed to the board without this bootloader present. (e.g. flashing the keyboard firmware's .bin using st-flash is insufficient).

  • See stm32duino's wiki page on Upload methods[3] for more details.

References

[0] https://docs.qmk.fm/#/flashing

[1] https://github.com/adafruit/tinyuf2

[2] https://github.com/rogerclarkmelbourne/STM32duino-bootloader

[3] https://github.com/stm32duino/wiki/wiki/Upload-methods

[4] https://electronics.stackexchange.com/questions/291402/stm32f4-taking-2-minutes-to-enter-dfu

[5] https://docs.qmk.fm/#/platformdev_blackpill_f4x1