"Some customers' devices are showing 'Connect to iTunes' after attempting an iOS update or a restore from iTunes on a Mac or PC," a statement to TechCrunch from Apple said.
"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.
"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."