Apple has issued a fix for the so-called “Error 53” bug, which rendered iPhones unusable when the home button was replaced by a third party component.

The problem came to light earlier this month when a software update from Apple saw anyone who had replaced a faulty home button with a part from a third party left with a phone that would not reboot. The error was caused by third party repair shops replacing broken or faulty home button assemblies, with the specific issue related to a connector linking the Touch ID sensor in a home button.

At the time, Apple called the update a security feature but it has now admitted that the piece of software it rolled out was never intended for public consumption and Apple is willing to reimburse those left out of pocket due to the issue.

“We apologize for any inconvenience. This was designed to be a factory test and was not intended to affect customers,” Apple said in a statement to TechCrunch. “Customers who paid for an out-of-warranty replacement of their device based on this issue should contact AppleCare about a reimbursement.”

Apple has also published a customer support document detailing what those affected by the bug should do.

To fix the matter, users will have to connect their iPhones to a PC or laptop and download the update (iOS 9.2.1) through iTunes as over-the -air updates will not work in this case. While the update will re-enable the use of Touch ID on affected phones, Apple sees this as a potential security issue.

Following the roll out of the software update last month, thousands of those affected reacted angrily, with some joining a class action lawsuit in the U.S. and an Australian consumer watchdog signaling that it was going to look into the matter.