Demystifying UEFI, the long-overdue BIOS replacement | Hacker News Reader

Demystifying UEFI, the long-overdue BIOS replacement

extremetech.com

39 pointsmrsebastian10 comments

The article seems a bit misinformed.

All of the UEFI systems I have encountered have native UEFI firmware in flash. On top of the UEFI environment, most shipping systems have a compatibility layer (CSM) that exposes a legacy BIOS emulation to allow traditional MBR-style booting. It is possible to load an EFI environment on top of a legacy BIOS (UEFI DUET), but that isn't usually how it is done.

There is no special bootloader; OS bootloaders are just UEFI applications in a specially-named path on each drive that the firmware finds and lists as boot options.

The mouse-driven GUI is a feature of some specific implementations, not part of UEFI itself.

If indeed some systems come locked down(secure boot) without an option to disable, couldn't Microsoft just make something like Apple's Bootcamp to boot alternative operating systems?

Would have to be the system vendor, not Microsoft. Or rather, if MS could do it then the whole scheme is a sham, the authentication is supposed to be at the firmware level, not in the OS.

UEFI is turning into a huge mess. I'd look to the Coreboot stuff being pushed/supported by AMD as a much better path to the future, and try to think of ways to club Intel's NIH-adled brain into getting on board.

Not like it hasn't happened before. Intel thought that IA64 was that way toward 64-bit, but AMD came up with the x86_64 that we use now.

The firmware checks the OS for a signature - Couldn't MS make a tool that booted a signed bootloader or whatever pieces the firmware needs to authenticate and then passes the boot process off to the alternate OS...

Not just the bootloader, from what I understand, the whole OS needs to be signed : drivers in particular or anything else that could talk to the firmware. So, they need to be signed too. With OSes such as Linux, I don't even know if it's technically possible to do that from a license point of view.

No, it is just the bootloader (same way the Android phones work), though MS could craft their signed bootloader to also verify the NT kernel (which would make sense).

The other problem is, in the original article that was published on this topic, that apparently the Linux/grub boot process will be changing so that the "kernel is part of the bootloader", so I think that adds to the complexity of the idea of signing either the bootloader or "the whole OS" (whatever that means anyway.

Yes, you are right. Actually, it's just the bootloader. So, technically Microsoft can come up with a bootloader (GPLed) that can boot Linux or modify the current one. My bad!

Regarding the "kernel is part of the bootloader" idea, I think that was just an idea :) That's not happening anytime soon, although you can give Linux as a stage 2 payload directly to coreboot currently.

And UEFI fans can still use it as a payload to coreboot! Although I am not sure why anyone would be a fan of UEFI. An extra layer of abstraction on top of BIOS ? Wait, why ?

According to the article, both AMD and Intel are on board with the UEFI.

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