Regarding T2 security chips `blocking` independent Mac repairs...
(iMore iPhone)

Is Apple`s T2 chip `blocking` independent repairs of new Macs, or is it providing hardware based tamper protection to keep those Macs secure? There`s a lot of confusion going around about Apple`s T2-based Macs, including the iMac Pro (2017), MacBook Pro (2018), and brand new Mac mini (2018) and MacBook Air (2018) and the trade-offs they make between security and repairability. Which is understandable. It`s a complex subject, perspective taking is hard, and the internet is terrible at juggling multiple truths. Apple likely sees T2 as a major advance in security for the vast majority of its customers at the expense of what is a small and shrinking part of the market that still wants to get inside and mess with the guts of their Macs. Independent repair shops probably see it as yet another blow to traditional, modular computing and their own business models. Where some see badly replaced screens and dangerously swapped batteries, others see overblown, overpriced repairs with no reason...