I discovered another problem with the calibration routine. Steps to reproduce: 1 - Perform a successful calibration 2 - Once the calibration is finished, move the head from the front left "home" position into the middle of the bed using the arrow keys in the gui. 3 - Power cycle the arduino (i.e. unplug the USB cable and replug it in). Problem 1: calibration doesn't remember the Y directon. I have to recalibrate. Problem 2: It thinks that the head is in the corner, and I can move the head towards the front, and to the right, but I can't move it towards the back or to the left of the original starting position. I have to recalibrate.