The T2 security chip is a Secure Enclave co-processor, which provides the foundation for the APFS encrypted storage, secure boot, and Touch ID on Macs, according to Apple’s own whitepaper. APFS is Apple’s own proprietary file system for Macs.
(Apple’s latest MacBook Air and Mac mini each come with the company’s new T2 security chip.)
The T2 chip could stop your computer from functioning unless Apple’s specific diagnostic software validates the parts being replaced. And that software is only located in Apple (Apple Service Toolkit 2 System Configuration Suite) stores and a small number of Authorised Apple Service Providers.According to an internal document from Apple obtained by MacRumors, the parts that the T2 chip currently affects are the MacBook Pro’s Touch ID board, display assembly, logic board and top case as well as the iMac Pro’s logic board and flash storage.
Despite that, the repair masters at iFixit bypassed diagnostics on a 13-inch MacBook Pro (2018) and successfully replaced the display and logic board. To be clear, iFixit is not an Apple Authorised Service Provider. Therefore, we can only assume that the diagnostics system isn’t currently in effect, yet. So if you’re looking to get your latest Mac repaired by a third-party store, you might want to do it as soon as possible.
Apple has also confirmed the same to The Verge that in case of repairs of parts like logic board or Touch ID the T2 will run checks for select replacement parts and whether they are from an authorised source or not.
Overall, the latest step is being seen as one that will further restrict third-party repairs for Macs. Also for those who like to fix their devices themselves, the newer Macs will pose a problem. Apple’s iMac Pro, Mac mini models from 2018, MacBook Air (2018) and new MacBook Pro models from 2018 all come with the T2 security chip.