The recent “Error 53” news which was originally broken by the Guardian in the article ‘Error 53’ fury mounts as Apple software update threatens to kill your iPhone 6 has caused quite a stir among many people.
There has been a lot of information flowing in the last few days.
Being one of the largest repair companies in the world means that we get insight into problems like this long before they reach the media.
The purpose of this blog post is to give readers an unbiased overview of the technical side of Error 53.
WHAT CAUSES ERROR 53
Error 53 is caused when an iPhone is restored when connected to a computer running iTunes via USB where the iPhone has a naturally failed or replacement home button/Touch ID part fitted.
Part of the restore process is called System Software Authorisation (page 6) where iTunes checks the device against the Apple installation authorisation server. It is at this verification step that the restore fails inside of iTunes with ‘Error 53’ and the iPhone is rendered a brick, completely wiped of data.
Below is a video we have recorded which shows the behaviour of iOS and iTunes when the Touch ID cable has failed or is replaced:
HOW DO THIRD PARTY REPAIRS CAUSE ERROR 53
It has been claimed in multiple articles that third party repairs directly cause Error 53. In short – they don’t.
A simple screen repair of your iPhone does not cause Error 53.
A battery repair of your iPhone does not cause Error 53.
Even a home button/Touch ID replacement on your iPhone does not cause Error 53.
No third party repair will directly cause Error 53 on your iPhone.
Error 53 is caused when the device fails the verification process when restored through a computer running iTunes when connected via USB (as described above).
Any customer / enquiry we have had since the iPhone 6 with a failed home button we have notified them that if the button is replaced then Error 53 is a huge issue and the Touch ID function will not be available on their handset – we always very strongly recommend against repair and recommend they visit Apple directly for a replacement handset.
ISN’T THIS ALL IN THE NAME OF SECURITY?
The Secure Enclave which stores all of the Touch ID related data is located on the logic board as part of the A7 processor – not the Touch ID (home button) part itself which is a seperate part located on the display assembly and connected to the logic board by a long extension flex cable.
The Touch ID part is a sensor that, when calibrated, interacts with the Secure Enclave, either authorising or declining a fingerprint.
Please take a look at our YouTube video above. Once the calibrated Touch ID part is removed and replaced with a seperate Touch ID part from a different handset the data stored inside the Secure Enclave does not appear to be accessible by the operating system. Not only this but the Touch ID function also fails when initiated at every point in the Operating System.
This would appear to indicate that the Secure Enclave protects itself as soon as the calibrated Touch ID part is disconnected.
Not in the video but also to note is that the iPhone 5S, the first iPhone to feature the Secure Enclave and the Touch ID feature, does not suffer from Error 53. When replacing the Touch ID part it removes the actual Touch ID (fingerprint sensor) functionality and access to the Secure Enclave yet the device will continue to function in every other way and will restore through iTunes without Error 53.
This would appear to indicate that the Secure Enclave protects itself from attack as soon as the paired Touch ID part is removed and that the verification process with the Apple installation authorisation server is not necessary.
HOW CAN THIS SITUATION BE FIXED?
When the calibrated Touch ID part is disconnected the Secure Enclave appears to protect itself from the rest of the Operating System. With this in mind we can’t see why the Apple installation authorisation server needs to fail the restore completely if just the Touch ID sensor fails verification during the iTunes restore. It would seem more appropriated for the device to successfully restore but with the Touch ID functionality disabled as it is with the iPhone 5S.
At present the only way to calibrate a new Touch ID is for Apple to use their in-store calibration machine. What would be ideal for the end user is if the Touch ID could be re-calibrated by the end user directly on the device.
We applaud Apple with the lengths at which they go to with design and security.
MY DEVICE HAS ERROR 53 – HOW DO I FIX IT?!?!
If your calibrated Touch ID part has failed then you can’t. You will need to visit Apple.
If your calibrated Touch ID part is still functional you will need to refit it when restoring the device inside iTunes.
We are not aware of any other permanent solutions to Error 53.