iOS Error 53 can occur and be displayed to the user after a failed Touch ID sensor is replaced and the proper repair procedure wasn't followed. In some cases, the iPhone was rendered unusable. The error most notably cropped up after iOS 9 was installed. Today, Apple apologized and posted an iOS 9.2.1 revision that un-bricks the iPhone.
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On February 18, Apple issued an update to iOS 9.2.1 (ver 13D20), provided an explanation and also an apology as reported by TechCrunch.
Some customers’ devices are showing ‘Connect to iTunes’ after attempting an iOS update or a restore from iTunes on a Mac or PC. This reports as an Error 53 in iTunes and 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.
Today, Apple released a software update that allows customers who have encountered this error message to successfully restore their device using iTunes on a Mac or PC.
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.
If your iPhone was rendered inoperable, you can connect it to iTunes on a Mac or PC, install the iOS update and recover the use of the iPhone.
The Confusion
Initially, some customers thought the worst of Apple because when they immediately took their iPhone into their local Apple retail store, repair was denied. The law firm of PVCA even considered a lawsuit. Now, Apple has provided a full explanation, apologized, notified their stores, and posted an iOS update.
This event reinforces the notion that nothing deeply technical with Apple is solved in an afternoon. Customers should most often wait, read, learn and Apple will generally make things right.
But then, a bricked iPhone is a bricked iPhone. Patience can often wear thin.