Arduino for STM32

hrm never saw this before but on weeacts micropython page for the blackpill the "correct" method of entering dfu is
Flashing via DFU

This board can be flashed using DFU. To put the board in DFU mode, disconnect USB, connect A9 to A10 and reconnect USB. Press and hold BOOT0. Press and release RESET ...

Altho ok in the start both my f411 anf f401 boards started to fail enumeration for usb dfu bootloader, not a switch problem because entering bootloadr via software only would have same results. In the end i fixed it 100 percent rock solid by adding a resistor from PA10 to ground. I used the first ...

so heres a quick and dirty kernel driver usb led class that works with unmodified arduino stm32 usb cdc config. The variable parsing is hackish but i didnt wanna put a lot of time into this one. It uses a 32neopixel bar as led class driver.