Chosen Solution
I have an iPhone 7 with a cracked screen otherwise fine (phone 1) and an iPhone 7 with a faulty cellular radio and an intact screen (phone 2). I would like to swap the screen assemblies so that phone 1 is fully functional. The repair video says that I have to transfer the Touch ID sensor from phone 1 to the screen assembly of phone 2 in order for Touch ID to work, but that seems like the most finicky part of the procedure. Can’t the Touch ID from phone 2 be used on phone 1 (i.e. after relearning the fingerprints)?
Unfortunately, the TouchID is paired between device and home button. Therefore, if you replace the home button at all, with a home button that is not the original home button the button will not function at all, TouchID or even clicking will not function. The only way to pair a new home button is with Apple’s software, but that is not available to the public. Swapping the home button is definitely the most difficult part, I recommend practicing on the screen from phone 2, that way if it gets damaged it won’t be an issue since that phone doesn’t work properly anyway.
