The people on the Asahi team explained this into great depth, but basically everything before macOS (bootloader and etc.) is capable of handling a different OS. However i would dispute their and OP's interpretation that Apple "supports" other OS. It's more of a "fitted for but not with", where Apple leave the technical possibility but don't do anything actively to help anyone trying to do so. The Asahi team has to reverse engineer pretty much everything from scratch with pretty much no documentation, which is an amazing feat and hats off to them. However claiming Apple supports what they're doing is a stretch, and there's no reason why Apple wouldn't just pull the rug under them - it's not like they've said it's OK (like with Bootcamp) to run Linux on Macs.
> "Okay, it's been over a year, and it's time to end the nonsense speculation."
> "I have heard from several Apple employees that:"
> "1. The boot method we use is for 3rd-party OSes, and Apple only use it to test that it works, because"
> "2. It is policy that it works."
> "Hacker News peanut gallery, you can drop the BS now. It's not an "assumption" that this stuff exists for 3rd-party OSes. It couldn't "be something internal Apple uses that could go away any minute". That is not how it works, it never was, and now I'm telling you it's official."
> "And this isn't even news because @XenoKovah (who invented and designed this entire Boot Policy 3rd party OS mechanism) already tweeted about this whole thing a long time ago, but apparently it needs to be restated."
This is conjecture with some wishful thinking. Apple providing the possibility of other OSes, and "inviting" Microsoft to port Windows, does not mean they want anyone to run any OS possible on Macbooks. And they don't do anything to help anyone write drivers for the Mac's numerous proprietary devices, everything has to be reverse engineered.
If Microsoft don't port Windows ARM to Macs, Apple might decommission the "core technologies". Even if they do, there's nothing stopping Apple from changing their mind down the lane, like they have already done on other topics, whatever the intentions of developers that developed them were.
Apple has implemented per OS security. Meaning that you could have complete chain-of-trust with one OS and have an untrusted second install of another OS. No PC has that, and it’s the core idea that allows Linux to be ported. I don’t see how such a useful technology for testing insecure versions of macOS would be removed. Apple backs few technologies, but they don’t often change their mind when they do. The fact of the matter is that Apple benefits from the access it gives Linux. It won’t remove it thoughtlessly.
Ultimately it leads to a discussion about the competition. When you buy an ARM based Surface, can you put Linux on it? Is Microsoft clear you can? Are they providing drivers?
The horse would be Apple putting out a public statement they want to have Linux on Macs. A few comments from developers that they made it on purpose so that other OSes could be booted on Macs is similar, but not even close.
Marcan, in case you are not aware, is one of the people behind Asahi. The only speculation here is yours. Parties directly involved have said otherwise. Hector Martin appears to have given up posting here exactly because of this kind of bullshit. Besides, even if Apple did come out and say it, you'd still trot this nonsense out.
Nothing. It's just bullshit naviety because apparently they haven't locked some aspect of the Mac yet, like they did with the iDevices, and so we are supposed to believe that this magnanimity from Apple is in "support" of other OS.