There are parts where basically only the interface to the hardware is different (example as in the article: bluetooth). But there are also many, many piece of h

There are parts where basically only the interface to the hardware is different (example as in the article: bluetooth). But there are also many, many piece of hardware that are bespoke. GPU, DCP, Interrupt controller and more. It's not really a serious hindrance with m1n1. As the communication can be snooped basically like using wireshark but on the hardware level. Don't get me wrong that doesn't make things easy. But it's definitely not an impossible task.