Apple has never looked kindly on third-party repairs for its devices, but the company said on Thursday that it didn't mean to brick iPhones whose home buttons had been fixed by an outside source. The Guardian reported at the beginning of February that a bug called "Error 53" was permanently disabling some iPhones running iOS 9 if their owners had gone outside of Apple for home button repairs.
Error 53 occurred when an iPhone's Touch ID sensor or the cables connecting the sensor to the motherboard was damaged or replaced during a repair. To secure stored fingerprint data, Apple uses special codes to match the Touch ID sensor with other trusted components. If the codes don't match, Touch ID doesn't work. But instead of just disabling Touch ID, Error 53 was bricking the whole phone without the ability to restore it.
Apple said in a statement to TechCrunch that it was fixing the bug.
Error 53 in iTunes ... appears when a device fails a security test. This test was designed to check whether Touch ID works properly before the device leaves the factory. ... We apologize for any inconvenience, this was designed to be a factory test and was not intended to affect customers. Customers who paid for an out-of-warranty replacement of their device based on this issue should contact AppleCare about a reimbursement.
Apple released a revised version of the iOS 9.2.1 update on Thursday to address Error 53 so iPhones won't become bricks just because they are repaired by a third-party. Touch ID will continue to lose functionality if component codes don't match—an important measure for protecting users in case untrusted parts contain malware—but third-party parts won't completely kill iPhones anymore.
At least Apple backed down instead of blatantly forcing users to bring their phones to the Genius Bar.