Arduino for STM32

But that STM32DUINO bootloader seems to have two modes, one for COM and one for HUD - correct. After some further tries and managed to compile it myself and start debugging. It now reports a COM port again, but when it does the check, whether the PC (or Raspberry for Klipper) wants to do an update ...

Hi all,
I have a Dremel 3D40 3D Printer, which uses a STM32F103RCT6. I want to install Klipper on that board and wanted to use the STM32DUINO bootloader, as this is one of the recommended boot loaders for Klipper.
I had to rewire the USB pins to the USB connector and used 22 Ohm series Resistors ...