To help get rid of this issue, we will introduce 4 workable methods to fix frozen iPhone 5 during iOS 9/8.4/8.2/8/7 update.
1. Force Restart Your iPhone 5
If your iPhone 5 does not have any response, you can force restart the device by holding down the Sleep/Wake and Home buttons simultaneously for around 10 seconds.
2. Reset Your iPhone 5 to Factory Settings
If your iPhone 5 keep freezing during iOS upgrade, and you can’t fix it through the force restart, you can try to reset your iPhone 5 to factory settings. Navigate to “Settings” >> “General” >> “Reset” >> “Reset all Settings”.
3. Reboot Your iPhone 5 with Reiboot
If you can’t fix frozen iPhone by force restart or hard reset the device, you can try a third-party software named Reiboot, which can reboot iPhone in the cases of recovery mode/red iTunes logo, Apple logo stuck and more freeze problem during iOS upgrade. Even when your iPhone's Home button is broken.
4. Restore Your iPhone 5 with iTunes
If the methods above still can not fix your frozen iPhone 5, you need to restore the iPhone with iTunes. Connect you iPhone 5 to computer, when it appears on iTunes, select the device and click on “Restore iPhone”, then click "Restore" in the pop up windows, follow the wizard and iTunes will automatically download the latest firmware used to update iPhone to the newest iOS. When it is finished, you can your iPhone again, but the frozen problem is fixed.
After your frozen iPhone is fixed, you also need to update the apps and remove the junk files to prevent your iPhone from freezing again, hopefully the 4 methods above can help you.