Chosen Solution
A family member gave me their old iPhone 6s plus to repair. They dropped it screen first and it broke the digitalizer but not the glass Bought a $50 screen replacement and swapped over the home button. Screen works, home button works and no error for the fingerprint sensor. But when I go to set up touch id it begins to “scan” but will error out within a second saying “keep finger on the home button until asked to lift”. It always seems to be less than a second and I haven’t gotten a single section of the scan to go through. I’ve tried unplugging and reseating the home button. I’ve reset the phone to factory settings twice and rebooted too many times to count. The button feels loose but doesn’t have give up or down. Does anyone know what could be causing this or why it’s happening? Is it possible the home button was damaged in the drop but showed no physical damage?
I have had a similar problem where the scan would take ages and you could not get it complete. My main thought was a dirty home button but cleaning it made no difference. It turned out to be the LDO beside the home button connector. They must have nudged it replacing the screen. I am not saying this is what is causing your issue but it is similar. If you feel competent you could rest a soldering iron on it for about 30 seconds and see if that fixes it. But be careful not to touch anything else.
