Hello Lucas - from what I gather if you are replacing the whole Earpiece and front sensor flex assembly on any iPhone with FaceID, FaceID will then stop working. This is because it is paired to individual iPhone, and when changed the phone knows it has been replaced so deactivates FaceID. You will need to use the original earpiece flex assembly to retain FaceID. So in short, yes, replacing the earpiece and sensor flex cable should deactivate FaceID sadly. Hope this helps (: