Chosen Solution
Hello, After changing my iphone screen i bought from ifix it the iphone disabled the face iD feature. Also, i replaced my battery with one from ifix it a went settings> about and it says unknown part for both screen and battery
did you transfer the original front flex this can cause face id issues if its not original or has been damaged, the screen and battery will show unknown part if its not the original part for that phone out of the factory. to fix the screen issue theres a chip on the old screen that needs swapped over to the new screen and pretty much the same for the battery it needs the bms circuit from the old original battery transferred over to the new battery and programmed
I had the same problem, I found that after a factory reset via macOS, and updating to iOS it immediately began working. Hope this Helps :)
It is always best to use a machine like an Apollo to transfer the Data from the Old screen and Battery to the new one. You will also have to reset the battery cycle to zero after transfer.
