can't flash over serial port after a custom build ...

[myklemykle]

Hi,

I've been experimenting with replacing arduino-cli, and I've gotten to the point where i can successfully build a fairly large sketch with cmake. (I'm using this fork of the Arduino-Cmake-Toolkit .) I'm looking forward to documenting that, once it's all ironed out.

The odd final problem I'm having is that after I flash my board with this newly built firmware, it no longer is letting me put it into RPI_UF2 USB Flash drive mode. Normally I twiddle the line mode with 'stty 1200' and it reboots into UF2 mode. Now it no longer registers as a serial port on my Mac when I plug it in.

As always, I built the sketch with UF2 mode selected as the upload method, and Adafruit TinyUSB (device) as the USB option. Cmake somehow built the binary differently than arduino-cli did, in this one problematic way. Everything else appears to function.

My question is: is the triggering of RPI_UF2 mode implemented by TinyUSB ? If so, I'll dig deeper in that direction. Or is it something in core? (Actually I thought it was implemented by the hardware, but apparently not?)

Thanks,
-mykle-

[myklemykle]

OK, I think this was failing because:

• The RP2040 core packages all of Adafruit_TinyUSB
• That includes ports to three other architectures (esp32, samd, nrf) that all define the same symbols as the RP2040 port
• Arduino-Cmake-Toolkit was finding all four architectures, compiling them, and handing them to the linker.

I will try to figure out a better solution than my current hackaround.