IPhone stuck on “choose a wifi network” after upgrading to iOS 15

Hello serious-user,

Thank you for reaching out to Apple Support Communities, and we'll be happy to help in any way we can. We understand you're having issues with your iPhone becoming unresponsive. Try the steps listed here to see if they resolve the issue: If your iPhone won't turn on or is frozen - Apple Support

"If your iPhone turns on but gets stuck during start up

If you see the Apple logo or a red or blue screen during startup, try these steps:

1. Connect your iPhone to a computer. On a Mac with macOS Catalina, open the Finder. On a Mac with macOS Mojave or earlier, or on a PC, open iTunes. Find out which macOS your Mac is using.
2. Select your iPhone on your computer.
3. While your iPhone is connected, follow these steps:

• On your iPhone 8 or later, including iPhone SE (2nd and 3rd generation): Press and quickly release the volume up button. Press and quickly release the volume down button. Then press and hold the side button.
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• On your iPhone 7 or iPhone 7 Plus: Press and hold the side button and volume down button at the same time.
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  • On your iPhone 6s or earlier, including iPhone SE (1st generation): Press and hold both the Home button and the side button or the top button at the same time.

1. Keep holding the buttons until you see the recovery mode screen.
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4. When you get the option to restore or update, choose Update.
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7. Your computer will download the software for your device. If it takes more than 15 minutes, your device will exit recovery mode. Repeat steps 2-4.

If you need more help

Contact Apple Support to set up service."

We hope this helps.

Cheers!