Using recovery mode
Apple iPhone 7 on iOS 15.0.0
If you're having problems updating or restoring your device, you can enable recovery mode to restore or update with the assistance of your computer.
Note: If you're having problems updating or restoring iPhone, you can enable recovery mode to restore or update with iTunes.
- 1.
Quickly press and release the Volume up button.
Note: For this tutorial, we're showing how to update iPhone using recovery mode. iTunes will try to reinstall iOS without deleting your data. You can choose to restore iPhone instead, but steps may vary based on what you choose.
Step 1/6 - 2.
Quickly press and release the Volume down button.
Step 2/6 - 3.
Press and hold the Side button until you see the Apple logo.
Step 3/6 
4.Continue to hold the Side button and connect the device to your computer.
Step 4/6
5.On your computer, click Update.
Note: After the update completes, follow the onscreen prompts to set up iPhone.
Step 5/6- Step 6 of 6:
You've completed the steps!
Step 6/6
