Apple's iOS 9 update has a little-known feature that disables iPhone 6 and 6 plus handsets that have been repaired by non-Apple technicians.

Users have found their iPhones rendered obsolete after they had their screen or home buttons repaired and then tried upgrading the software. The software issue has been called the "Error 53" problem, and it doesn't have a quick fix.

"The iPhone 'iPhone' could not be restored. An unknown error occurred (53)," reads the message that indicates a phone has been frozen.

"Bricking [disabling] the phone so that you can't even recover the photos on it is ridiculous. Imagine, for example, you go on honeymoon to somewhere really pretty that doesn't have an official Apple store. You take some pictures of you and your beloved with your iPhone. Unfortunately you drop it, and break the home button. You get it fixed at a local repair place and take a few more gorgeous photos. Then the phone updates and [...] YOU GET NOTHING," user iey404 said on Reddit.

The error is a way to ensure that the iPhone's security hasn't been compromised, according to Apple.

It comes about when a phone is repaired by an unauthorised third party that can't re-validate the iPhone 6 or 6 plus' touch sensor after it has been tampered with.

Improvements to security in the iOS 9 update means that repaired phones display the "Error 53" message - even if they have been working for weeks or months after the repair. "When iPhone is serviced by an unauthorised repair provider, faulty screens or other invalid components that affect the Touch ID sensor could cause the check to fail if the pairing cannot be validated. With a subsequent update or restore, additional security checks result in an Error 53 being displayed," said an Apple spokesman.

"Without this unique pairing [betweeen the touch sensor and "secure enclave" in the phone], a malicious Touch ID sensor could be substituted, thereby gaining access to the secure enclave. When iOS detects that the pairing fails, Touch ID including Apple Pay is disabled so the device remains secure".

Apple advises anyone who has experienced the problem should contact them, visit an Apple store, or an authorised Apple provider.

"We take customer security very seriously and Error 53 is the result of security checks designed to protect our customers. iOS checks that the Touch ID sensor in your iPhone or iPad correctly matches your device’s other components. If iOS finds a mismatch, the check fails and Touch ID, including for Apple Pay use, is disabled. This security measure is necessary to protect your device and prevent a fraudulent Touch ID sensor from being used. If a customer encounters Error 53, we encourage them to contact Apple Support," they added.

Telegraph.co.uk