macOS Big Sur 11.2 beta 2 adds full custom kernel support | Hacker News Reader

macOS Big Sur 11.2 beta 2 adds full custom kernel support

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I am streaming the M1 bring-up process right now: https://youtu.be/d5s9fYfvzmY

Currently working on the bootloader/research tool.

Splendid, thanks for this :)

This is fascinating, thanks. Very good for soaking up low level concepts

What does this mean exactly?

EDIT:

https://news.ycombinator.com/item?id=25773611 answers this

     As far as I'm aware the tool (probably Disk Utility I think?) on macOS that allows you to replace the bootloader etc now supports non-macOS replacements.

Their wiki has some interesting information on how the M1 boot process works in comparison to a UEFI PC.

https://github.com/AsahiLinux/docs/wiki/M1-vs.-PC-Boot

Does this practically mean I will be able to replace macOS on Apple hardware with Linux with Apples blessing?

yes. However that Linux will not be very useful because there are no drivers for the machine and Apple is not documenting any of their hardware to the point that people could easily write drivers.

This will be a huge reverse-engineering effort.

We went through that last time with their sad attempts at UEFI compliance.

So long as they allow the possibility it will happen.

In other news, they allow firewalls to work as designed in this release. So some kind of sanity may be taking hold.

>So long as they allow the possibility it will happen.

AFAIK there is still no support for the T2 disk controller even though T2 macs are a thing for 4 years now.

I'm sure it will eventually happen, but don't hold your breath.

AFAIK it got merged a while back: https://github.com/torvalds/linux/commit/66341331ba0d2de4ff4... (for Linux 5.4)

It isn't even a big patch.

This myth keeps coming up. The T2 disk controller is just a normal NVMe controller with a couple nonstandard quirks. There is upstream support now.

It took a while to work out because nobody sat down and got it done on day 1. This could've been worked out within 24 hours of the T2 macs' release, working at the pace at which I expect to be working on M1 bring-up.

The reverse engineering is full-steam-ahead, a post about the GPU:

https://rosenzweig.io/blog/asahi-gpu-part-1.html

How that will actually work? Google does not give more details.

As far as I'm aware the tool (probably Disk Utility I think?) on macOS that allows you to replace the bootloader etc now supports non-macOS replacements.

$ kmutil configure-boot -c loader.macho

loader being a Mach-O executable that iBoot will jump to. After that everything is for you.

Note: the command should be executed from macOS 1 True Recovery (hold the power button for the first few seconds at boot up) to downgrade the security policy.

Thanks for the command. I found this by searching " kmutil configure-boot":

https://twitter.com/never_released/status/133975317062974669...

the MBA of @marcan42 seems l̵i̵k̵e̵ ̵I̵n̵t̵e̵l̵ ̵b̵a̵s̵e̵d̵,̵ ̵i̵f̵ ̵M̵1̵ ̵i̵s̵ ̵a̵v̵a̵i̵l̵a̵b̵l̵e̵ ̵t̵o̵o̵ (it's M1 acturally) it means we can boot other OS on M1?

The MBA in the video is an M1 Mac.

oops, thanks

I'm curious as to Apple's angle here. They have always had a closed ecosystem, so I'm wondering what made them change their approach so drastically.

Mac.

AFAIK this was always planned for the m1 macs

I'm not sure there's ever been a Mac where you couldn't boot your own OS. Maybe the very, very early ones, but Linux for the later M68k and PPC Macs was definitely a thing.

Personally, I will only consider a mac if there is the option to run Linux.

I used to support a lab of triple-bootable Macs—macOS/Windows/Linux.

Current macOS is more locked down due to privacy and security threats primarily, not because Apple doesn’t want you to boot a non-Apple OS.

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