Techcrunch:

Today, Apple is issuing an updated version of iOS 9.2.1 for users that update their iPhones via iTunes only. This update will restore phones ‘bricked’ or disabled by Error 53 and will prevent future iPhones that have had their home button (or the cable) replaced by third party repair centers from being disabled.

A new support document on Apple’s site has been issued that details the causes and repair methods for Error 53.

Good move on Apple’s part to make this right.