Extruder troubles: Filament feeder keeps jumping back


Do we need the 1.05V ref only for the extruder stepper driver?
Or should X/Y/Z also set to 1.05 (mine showed ~0.75 on all four stepper drivers)


As long as you don’t have issues with the axis drivers, just stick with the default values. The preset (and measured) voltage refers to a certain motor current, which translates to a certain torque. The relationship is explained in the motor controller datasheet. If it ain’t broken, don’t fix it.