We’ve heard a lot about the iPhone 4S’ battery life after it gets bumped up to iOS 7. It drains down a treat, infuriating owners, while the iPhone 5 seems untouched.
We heard from a few people who’ve updated and have found their iPhone 4S dying in just hours, so we looked into the problem and in our infinite collective wisdom found a solution.
Battery drain is a huge problem, and it’s something we saw after the iPhone 4S went up to iOS 6 last year. It’s not a hardware problem, it’s related to how you install iOS 7.
Tests showed that the iPhone 4S drained very rapidly, and the phones seem to be stricken at random, but it actually happens when you do the update under certain conditions. We know how to avoid these conditions.
You have to make a back-up of your phone in iTunes DFU mode, then do a clean installation of iOS 6. To enter DFU mode, hold down the wake/sleep buttons until you see the Apple logo. Then you must keep the home button depressed until you hit recovery (which sounds almost medical!).
When you’ve installed iOS 6, you can install iOS 7, then reinstall all your data. If you want to revert to iOS 6, you can do so, as long as you backed up in DFU.
The iPhone 4S battery drain problem is a huge one, but it’s easy to sidestep it by making a clean update then reinstalling your data.