I've recently burnt my potentiometer on E0 so the motor isn't working properly anymore. I want to use it on E1 instead. If you have any better idea how to fix this instead of changing code in firmware, feel free to share.
the fastest way is to slice using two extruders and assign all print work to E1. Set the head offsets to [0,0] and that shall do the job.
The harder is to edit pins file and do remapping.