It’s a second-hand unit, the belts and belt gear ring were pretty thrashed so I changed them last night. Inspected everything and made sure the gears were not too tight — seems to run better now. The frame is built to spec with some extra cross bracing and sitting at a 15° angle from vertical. I also updated the firmware to v0.83.
Do you think any settings could have persisted from the previous owner despite a firmware update? Looks like he had some trouble with it and possibly changed some settings. Here’s one of his threads M4 Calibration Questions - #47 by KDB