Who knows what performance Apple's mobile phone baseband has broken?

I'm an Apple maintenance engineer. Let me talk about it.

1. There may be something wrong with the baseband, which is a hardware failure. You can go to the factory for free replacement.

2. Turn off the phone and restart it. The method is:

Click "Turn Up the Volume" quickly before releasing, and click "Turn Down the Volume" quickly before releasing.

Finally, press and hold the "side button" until the iPhone restarts and the Apple logo appears.

3. If you just inserted and unplugged your sim card, you may encounter this problem, which may be due to poor contact of the sim card. It should be enough to reinsert the SIM card after turning it off.

4. If you just upgraded the ios system, turn the airplane mode on and off. Just repeat the operation several times.

5. The requirements for free after-sales warranty are: 1. Bank of China is under warranty. 2. Non-human failures, water ingress and falling are not guaranteed. 3. There are invoices.

6. If it is not covered, it can also be repaired. Motherboard problems don't have to be changed. A motherboard consists of dozens of chips, which can cost several hundred yuan for ordinary conventional chips, and 34,000 yuan without replacing the motherboard. Most of them are baseband desoldering or baseband power supply replacement.

7. If the "Demodulator Firmware" is blank, or an exclamation point appears at the top right of the screen, it is basically a baseband problem.

8. That's all. If I don't know, I'll talk about it in detail. V my id tea is the same number.