Having purchased a purportedly authentic OEM Apple glass back on eBay (from a 200,000+ UK based seller), which turned out to be fake and broke within a day, I embarked on a journey to the Apple store to get a certificate proving it was counterfeit thus allowing me to get my money back from Paypal. After replacing the glass back, the "genius" gave me a "slap on the wrist" "I've replaced the back, but I'm going to have to give you a slap on the wrist. Firstly, the quality of this glass back is shocking, it could easily have damaged your battery or other parts of the phone. By changing it yourself, we should really count it as a voided warranty. "Secondly, your iPhone is hacked. Hacked iPhones are not covered by warranty and were something wrong with it, we wouldn't fix it. Please un-hack your iPhone next time you come to the Apple store."