I installed the following firmware https://github.com/iGEM2016-LMU-TUM/UM2.1-Firmware/tree/bioink on my UM2+extended.
It is a modified version of the Marlin/Sprinter-firmware for using a second stepper-motor, as well as disabling the nozzle- and buildplate heating, for my intention is to use a syringe for printing.
After installing I tested the new setup with a simple pattern: the printer starts printing without any problem, but doesnt start the second stepper-motor and freezes after finishing the printjob.
Next tests: the problems switch between error 06 (z-axis switch is broken) and error07 (x- and y- axis are broken).
did anyone expirience a similar problem?