How To Factory Reset Your Apple iPhone 4S - Factory Reset
Apple iPhone 4S - Reset device - AT&T
iPhone 4s - Wikipedia
Can't activate iPhone 4s. I just factory reset it through the settings app and it won't activate now. It's running iOS 8.4.1 and I DON'T want to update it to iOS 9.3.6.
iPhone 4S Troubleshooting - iFixit
How To Reset The iPhone (Hard, Soft and For All iOS Versions) | Ubergizmo
How to Hard Reset Apple iPhone 4s - Swopsmart
Micro Center - How to reset the Apple iPhone 4S to Factory Settings