I was able to successfully swap a damaged (water) screen on my old iPhone 6 plus with this guide. Just an observation that may help others in the future. I moved the TouchID button from the original screen onto the new one. Once I fired up the phone after re-assembly, I got an “Unable to activate TouchID” message, but the home button still functioned for all other tasks like exiting an app and going to home screen, double pressing for app cards which showed what apps were still open and running. Only thing it didn’t do was accept fingerprints for security or purchases. I tried restoring phone, rebooting phone, reinstalling iOS. Nothing worked. Finally read about swapping out the original TouchID ribbon cable from the original screen. Removed the TouchID ribbon cable from the new screen I purchased from iFixIt and used the original TouchID cable and voila! TouchID functionality restored. So……probably a bad TouchID ribbon cable on the new screen, but an easy enough fix.