Project Inspection -> Error: register r24, r26, r28 or r30 required

Yep, your prophecy turned out 100% correct (I used pre-debug button

because I like GUIs :wink:)

I think I’ll do some deep-dive into this tomorrow. Unfortunately, as the linker fails in firmware.elf, I don’t even know which file it doesn’t want to eat. Can I somehow decode the cryptic cc8IFU2J.s thingy?