Well, if one of the pins (part of the SIM connector) is broken, you can repair it by soldering or resoldering (desolder the first one and solder the new one) the SIM connector.
Great video. You make it look easy but it's not. :(
Tried swapping out motherboards (putting a C5306 board from a crappy body into a nice C5303 body so it gets LTE on T-Mobile) but could not get the top left corner screws on BOTH phones to come lose. Also could not get the middle screw on the bottom of one of them to come out. Had to give up. Very frustrating... :((
They are the same size as what you took out but mine were so tightly screwed in, they wouldn't come out. Now the head of the screws are stripped. All other screws came out without problem.
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2021-04-23YouTube_Question
2021-04-23