You may need to use recovery mode if you're having trouble restoring your iPhone using iTunes or macOS.
Using a USB to Lightning Cable, connect your iPhone to a computer running the latest version of macOS or iTunes.
Press the Volume Up button, then press the Volume Down button, then press and hold the Side button.
Don't release the button when you see the Apple logo. Keep holding down the Side button until you see the recovery mode screen.
Your computer will popup a message letting you know that there is a device that needs to be updated or restored.
To exit recovery mode, press the Volume Up button, then press the Volume Down button, then hold down the Side button until the Apple logo appears.
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