known issues:
- flash-based params does not work on H7 (due to ECC), so params are on
SD card. The last flash sector is still reserved however.
- output channel 6 does not support DShot (the implementation does not
handle channel gaps)
- flashing of the 2. flash bank is much slower (around 3x), than the 1.
bank for some unknown reason.
- after the BL jumps to the app, there's several seconds passing until
stm32_boardinitialize() is called.
Beat Küng