USB Bootloader for STM32u0

[BlakeFreer]

See ST Application Note 2606

[BlakeFreer]

I got the built in USB boot loader working on nucleo. I can program it over USB with STM32CubeProgrammer and with dfu-util.

Is this issue still necessary?

If yes, consider using embassy-boot

[BlakeFreer]

Is this issue still necessary?

Yes, the embedded bootloader from STM configures the USART3_RX pin in a way that could damage an FPGA spi line by pulling it high when the FPGA is powered down.

Embassy boot looks promising