I had trouble getting my Mac to recognize it plugged in, even in DFU mode. Had to reboot my Mac a couple times. I saw someone else on Reddit say that eventually their Mac recognized the iPad and it stopped respringing on them. I was messing around with it for about a half hour before giving up and going back to 14.7. A clean install on 15 worked fine for me though, as soon as I reset it and restored my back up, it broke again.The restart did not solve the problem, it kept respringing. Only after I plugged it in, it suddenly stopped.