Ok, forget about the above. Me being an Arduino-agnostic didn't really know how the bootloader works. When AVRdude says "I'm done" I didn't bother looking further into what was done. Most of the cases it was a timeout as I didn't know when or how long the bootloader was available after reset. The LED doesn't flash so I guess I got it right by sheer luck a couple of times but not when I enabled the heatbed sensor...
Oh well, one learns...
/Jan
Oh well, one learns...
/Jan