The iPhone 4S battery problems continue! Even a software update that was supposed to fix the problem couldn't fix the problem. So what's going on? Is it a software bug? Maybe. A hardware flaw? Probably not.
ZDNet had an app developer test out two different iPhone 4S devices, one with the battery problem—rapid drop in battery when the iPhone was idle—and one without the battery problem. They were both bought at the same time, both running iOS 5.0.1 and both on AT&T. They should both have the same battery life but why was one draining faster than the other?
The app developer wanted to see if it was a hardware issue so he backed up both phones and factory reset both of them. He then restored each device with the different backup. The phone that originally had the battery problem was restored with software from the phone that didn't have a battery problem, the phone that didn't have the battery problem was restored with software from the phone that did have the battery problem. If the battery problem was caused by hardware, the same phone that had the battery problem would still have the problem, right? That wasn't the case. Instead, the battery problem jumped phones through software.
The phone that previously drained fast now showed excellent battery life and the phone that was previously excellent, now drained fast. The problem, according to this sample of one test, shows that the battery issue is in the software and not the hardware. Which means it should be fixable. So fix it, Apple. [ZDNet]