Chosen Solution
I ordered a screen replacement for my iPhone 7 from ifixit and proceeded with the fingerprint scanner swap. I followed the instructions to a “T” and everything went swimmingly and tested it before closing the phone back up. Even the fingerprint scanner worked flawlessly. However, after completely closing the phone and booting, it is now stuck in a boot loop. I had not touched the sensors or cables.. What could be the problem?
This sounds like a connector problem. Start by opening the phone back up and reconnect and reseat all the connectors that you removed including the battery. If that doesn’t fix the problem try booting with the front camera flex assembly disconnected.
