Chosen Solution
So i was replacing the screen on a iphone x, when i was testing the phone after replacing the screen i noticed that when it would boot up and when i would put in the correct passcode to unlock the phone, the screen froze and just restarted, but heres the twist, if i dont plug in the ear speaker, the long flex connected from the screen to the motherboard, the phone boots up and when i put in the password it unlocks perfectly and i can use it fine, ofc without the ear speaker and face id working, but its a customers phone and i need some help, i also did examine the flex and everything, nothing was damaged, this also is happening to an iphone 11 i was repairing and i havent seen it happen over the hundreds of iphone x’s and iphone 11’s ive done, if someone can please help that would be amazing!
The ear speaker component contains a few different modules; the ambient light sensor, proximity sensor, ear speaker, top/front-facing microphone, and FaceID sensor. If just one of them were damaged during the transfer, it may cause a short which will cause the device to malfunction (freeze or reboot). In your case, based on when this symptom arises, I’m inclined to say that the FaceID sensor might have been damaged. It makes sense for iOS to attempt a FaceID scan during the unlock process, which is when your customer’s phone bricks. Before deeming it a bad unit, I would definitely verify that the board connection is free of any dust or debris that may be obstructing it by re-seating the flex, and follow that with a hard reset. If you’re still in trouble, I would then test a known-good ear speaker component and check for the original symptom. If the known-good resolves the issue, the original part was damaged in some way unfortunately.
Did you test and confirm FaceID and the earspeaker were working before you opened it up? I’m wondering if there’s a short somewhere in the assembly that’s causing these issues.
