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#1 2012-10-08 17:59:32

Ledti
Member
Registered: 2010-07-31
Posts: 122
Website

UEFI vs legacy booting

With the latest Arch ISO now supporting EFI booting, I'm curious to know if there are any strong benefits in using a pure UEFI setup rather than just using legacy mode with a GUID partition table. I currently don't see any good reason to go through all of the extra steps of creating a EFI System partition, creating boot entries with efibootmgr, and etcetera, but I'm curious to understand all the hype surrounding the topic.

As a user I understand the benefits of having a UEFI motherboard vs an old BIOS motherboard. It's fast, graphical (mouse), very configurable, and flashing it is simplified. The strengths of GPT are obvious too. But I don't understand the benefits of booting with UEFI mode when my suspend/resume and booting times are already essentially instantaneous while using the legacy mode. If you're not forced into booting with EFI, is there any good reason to use it as a simple desktop/laptop user?

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#2 2012-10-08 20:59:58

Inxsible
Forum Fellow
From: Chicago
Registered: 2008-06-09
Posts: 9,059

Re: UEFI vs legacy booting

Moving to GNU Linux Discussion


Forum Rules

There's no such thing as a stupid question, but there sure are a lot of inquisitive idiots !

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#3 2012-10-08 21:24:15

litemotiv
Forum Fellow
Registered: 2008-08-01
Posts: 5,026

Re: UEFI vs legacy booting

The two main reasons why i use EFI boot are:

- my laptop doesn't support ahci in bios mode
- no bootloader needed


ᶘ ᵒᴥᵒᶅ

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#4 2012-10-17 03:38:06

bsilbaugh
Member
From: Maryland, USA
Registered: 2011-11-15
Posts: 141

Re: UEFI vs legacy booting

litemotiv wrote:

no bootloader needed

Technically, a bootloader is still required (UEFI Bootloaders). However, the kernel does have a built-in UEFI bootloader--which is perhaps what you are referring to.


- Good judgement comes from experience; experience comes from bad judgement. -- Mark Twain
- There's a remedy for everything but death. -- The wise fool, Sancho Panza
- The purpose of a system is what it does. -- Anthony Stafford Beer

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#5 2012-10-17 03:47:48

bsilbaugh
Member
From: Maryland, USA
Registered: 2011-11-15
Posts: 141

Re: UEFI vs legacy booting

I use EFI boot because it is the only way I can dual boot OS X and Arch on my MacBook.

EDIT: Well... technically I could boot Arch using BIOS emulation, but its messy on the Mac.

Last edited by bsilbaugh (2012-10-17 03:49:09)


- Good judgement comes from experience; experience comes from bad judgement. -- Mark Twain
- There's a remedy for everything but death. -- The wise fool, Sancho Panza
- The purpose of a system is what it does. -- Anthony Stafford Beer

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#6 2012-10-17 04:20:25

WonderWoofy
Member
From: Los Gatos, CA
Registered: 2012-05-19
Posts: 8,412

Re: UEFI vs legacy booting

That is one area i really wish apple would ahve adhered to the standard instead of making thier own funky setup with the half a$$ed legacy bios mode.

As far as UEFI vs legacy, I set it up simply because my system supported it and I wanted to learn more about it.  After getting things going, I realized a couple things that were prett cool. 

First, if you set up UEFI, it has no bearing on the ability to still user legacy bios.  So I actually have it set up so that I have syslinux as a backup, just in case.

Second, I really like the whole idea of having no bootloader (as bsilbaugh mentioned, it is the kernel EFI Stub Loader).  The only caveat would be that you have to make an efibootmgr entry with the kernel parameters.  So changing boot parameters is not quite as easy as with a traditional bootloader.  For these instances, I really like the UEFI shell, as it is incredibly reliable and allows for booting anything you want as long as it resides in one of your EFI system partitions.

Third, I love the fact that because FAT is so universal, I can actually use my ESP as my /boot partition.  Thus, really eliminating the messiness of having a /boot and a /boot/efi.  So kernel updates and everything are super simple.  The only thing is that I noticed my system would boot the kernel as is from the UEFI shell, but from the efibootmgr entry it requires the kernel be appended with .efi, so I have a service/path setup to take care of this with systemd.

Honestly, if you are happy with your current setup, I see no reason to go out of the way to change what already works.  Especially since, at present, the UEFI standard does not quite result in total consistency from system to system.  You often see repots of some buggy firmware doing some really strange things.  In one thread I remember one person reporting that their system was like windows in that it would only boot uefi/gpt or mbr/bios, and mine acts funny if the kernel is not in the root of the ESP. 

Also, if you have to reset your bios, for whatever reason, your bootloader entries go with it.  In my case, even my UEFI shell is a bootloader entry, so to restore it, I have to get an installer disc out, switch off bios mode, and then boot from that in order to create the entries again (havne't had to do this yet though).

If you do end up going gpt/bios, I would certainly recommend going with syslinux though.  It is much simpler, and you don't have to do the silly 2MB non-filesystem boot partition like grub. 

Sorry for the long post, I hope this might help.

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#7 2012-10-18 19:08:03

Ledti
Member
Registered: 2010-07-31
Posts: 122
Website

Re: UEFI vs legacy booting

I did decide to use GPT/mbr with Syslinux since there are no drawbacks in using legacy mode with my motherboard (ASRock 890GX Pro3). I also prefer having Syslinux as my bootloader as it's very robust (hidden w/ timer, memtest86+ and HDT entries, etc). I did learn a lot while using the *gdisk programs in the gptfdisk package, and now I have a nice partition setup.

Thanks for the replies, especially WonderWoofy, as they're informative and I'm sure others are curious about this question as well.

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#8 2012-10-19 02:13:06

WonderWoofy
Member
From: Los Gatos, CA
Registered: 2012-05-19
Posts: 8,412

Re: UEFI vs legacy booting

Do posts in GNU/Linux Discussion warrant a [Solved]?  If you think so, mark it as such... otherwise, ignore this noise.  BTW, glad my post was helpful.

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