You may have a firmware issue with endstops. You can use M119 to query the status of the endstops. If any come back High (H) you'll need to adjust firmware to match your endstops.
Also it would help if we knew what drivers and motors you are using. What is the max current of the stepper? What is your driver supposedly outputting at 0.5V? Not all "Pololu's" are the same as there are a lot of clones out there.
Is the stepper locked tightly in place when the current is on? If not you are likely not driving with enough current.
Bryan
Also it would help if we knew what drivers and motors you are using. What is the max current of the stepper? What is your driver supposedly outputting at 0.5V? Not all "Pololu's" are the same as there are a lot of clones out there.
Is the stepper locked tightly in place when the current is on? If not you are likely not driving with enough current.
Bryan