The reason behind the unresponsive iPhone screen might be the iOS update. Sometimes, software updates may cause unpleasant system reactions. The good news is that such issues are usually minor and can easily be resolved by applying some workarounds.
If your iPhone is not responding, we recommend you try force rebooting the device first:
- Press Volume Up once.
- Press Volume Down once.
- Press and hold the side button until you'll see the Apple logo.
The Unlocking process is used when you can't get by the passcode (Passcode Unlock) or if you want to use the device with a SIM-card from a different carrier (Carrier Unlock).
Anyways, in the worst case scenario you might need to contact certified Apple service centres or private contractors in order to make your iPhone boot up again.