My iPhone went dead! How do I fix it? - AppleToolBox
Read this before upgrading your iPhone 4s to iOS 8
iPhone Battery Replacement – iPhone Motherboard Repair Center
iOS 8 on the iPhone 4S: Performance isn't the (only) problem | Ars Technica
Update iPhone 4 to iOS 8 or 9 - Is this Possible?
Help] iPhone 4s 32gb iOS 8 Jailbroken after restart automatically set it time to the epoch and disabled, Is there any way to unlock it wothout losing data? : r/jailbreak
How to Fix iOS 8.1 Battery Life
iOS 8 on the iPhone 4S: Performance isn't the (only) problem | Ars Technica
iOS 8 on the iPhone 4S: Performance isn't the (only) problem | Ars Technica
Looking inside an iPhone 4/4S battery | Rip It Apart - Jason's electronics blog-thingy