We made a mistake on the firmware on the first shipment of printers. When we were testing the firmware built, we tested it on our first prototype which had a 50mm spacing on the top for the end stop switches. After KS-001, we changed this to 60mm for two reasons: 1) the extra 10mm space made it easier to wire the end stop switches, and most importantly, everyone's kit shipped with a 60mm spacer - the leg of the upper triangle vertex. However, when we moved those end stop switches, the entire coordinate system of the printer shifted down by 10mm, and therefore the probe overtravels on the retraction sequence, causing the drive system to loose steps. We realized what was going on when the first initial feedback came back on the forum, and we fixed it on all the printers that were shipped in the most recent shipment. (As an aside, this is why you invest in good tooling and fixturing; Mike was able to test and reprogram 100 additional boards very quickly due to our panini press fixture. It was considered to be better than opening up 100 sealed controller cards and reprogramming and resealing them. Those boards will go onto Amazon when we are back from vacation). If you have a printer that was in the original shipment, you likely will need to adjust the firmware setting in configuration.h on the firmware. I don't have the firmware handly; I'm on my wife's laptop now, it's 6am where I am and our next flight leaves in 3 hrs, but I will do more project documentation and firmware / code release when I get to my final destination. If for some reason people can't flash their firmware; we promised a plug and play printer, and we'll cross ship boards if necessary to make that happen. But we'd like to work with people on flashing their firmware first.