I can confirm this method works. But still, I am going to post my steps. I literally created this Samsung community account just to post this.
My wife's Z Flip 4 got an update on 1st July 2024, after that, no service. Can't change mobile network selection to manual (it automatically changes back immediately like a glitch). Tried everything.
Now, I had a failed attempt which is:
Assuming my wife's Phone as Phone A(which had the no service issue) and my phone as Phone B.
Failed Attempt:
- I Ejected Phone A's sim card, and tried another sim card, Didn't fixed it.
Successfull Attempt:
- I ejected BOTH Phone A's and Phone B's sim card,
- Inserted Sim B to Phone A;
- Inserted Sim A to phone B.
- A prompt came to both phones to restart it, which I did.
- Kept it like a minute or 2,
- Then swapped BACK the Sim A to phone A and Sim B to Phone B,
- A prompt came to both phones to restart it, which I did.
- Got service on the Phone A. Fixed!!!
Thoughts: It changed something inside the sim A chip during the update I guess. When I put it inside phone B, the sim chip got reset or something maybe? Anyway. It worked.
