Arch Linux

z_Zelman

Member

Registered: 2013-01-23

Posts: 7

Need help understanding a GPT partition table for a UEFI motherboard

Hello, I have a MSI Z77A-GD65 motherboard with a 256GB SSD and I would like to understand the partition table that would allow me to run Arch with this setup.

I know that I need to use gdisk to make the GPT partition table, FAT32 partition that is  greater than 512MB, and how to format that FAT32 partition thanks to the wiki. But I need help understanding the following: where the FAT32 partition needs to be in relation to the others, do I still need a normal boot partition (like one for a non-UEFI motherboard), what goes in the FAT32 partition, and what boot loaders do I need?

I guess it would really help a lot me if someone showed me a correct GPT partition table.

I'm sorry if this is a completely newb post, but I'm really confused about what a UEFI motherboard needs for a partition table

graysky

Wiki Maintainer

From: :wq

Registered: 2008-12-01

Posts: 10,731

Website

Re: Need help understanding a GPT partition table for a UEFI motherboard

My SSD is sda and it boots with grub-efi-x86_64.

/dev/sda1 is 250 MB and is the EFI system partition
/dev/sda2 is 250 MB and is /boot

The rest of my drives are partitions for my system, home, var, data, and other partitions for other uses which aren't relevant to your question.

All your questions should be answered in the grub wiki article.

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teateawhy

Member

From: GER

Registered: 2012-03-05

Posts: 1,138

Website

Re: Need help understanding a GPT partition table for a UEFI motherboard

Do I still need a normal boot partition?

With the boot manager rEFInd it is now possible to have a combined /boot and EFI system partition, you do not need two seperate partitions anymore. That way new kernels are copied to the EFI partition by pacman, because it is mounted at boot.
(@graysky
Although i do not know if this is relevant for grub-efi at all.)

srs5694

Member

From: Woonsocket, RI

Registered: 2012-11-06

Posts: 719

Website

Re: Need help understanding a GPT partition table for a UEFI motherboard

z_Zelman,

The FAT32 partition to which you refer is presumably the EFI System Partition (ESP). Its location on the disk is unimportant, both in terms of the partition number and where its sectors are relative to those of other partitions; however, at least one tool (efibootmgr) uses a default partition number of 1 for the ESP, so there's slightly less chance of a user error causing problems if you make it partition #1.

The ESP holds boot programs (boot managers and boot loaders) and related files. There are several choices for boot programs; in fact, I've written a Web page on the topic. My rEFInd and gummiboot are popular boot managers in the Arch community. Both of these programs are best used in conjunction with the kernel's built-in EFI stub loader (available in 3.3.0 and later kernels). Some users forego rEFInd or gummiboot in favor of the EFI's own (much more primitive) boot manager. Most other distributions use GRUB 2 for EFI-mode booting.

I'm guessing that by "normal boot partition" you mean a BIOS Boot Partition, which is used to store GRUB's 2nd-stage code for BIOS-mode booting on GPT disks. If so, then you do not need such a partition when booting in EFI mode. Creating such a partition won't hurt, except to clutter your partition table and to chew up a tiny amount of disk space, but it won't help, either. Under EFI, the ESP and the files that reside inside it take the place of the BIOS Boot Partition.