Arch won't boot with GPT

gsingh93 · 2013-11-30 03:17:13

I just wiped my desktop's hard drive and tried to install Arch. I wanted to use GPT, but when I finished the installation, I wasn't able to get it to boot (no bootable medium was detected). I then tried using MBR, and I was able to get it to boot (after making the /boot partition bootable with fdisk, which wasn't in the beginner's guide).

I want to use GPT though, not MBR. I made 7 partitions, with /dev/sda1 being /boot and /dev/sda7 being the BIOS boot partition required for GPT. The BIOS boot partition starts at sector 34 and ends at sector 2047 according to gdisk. The BIOS boot partition has the bios_grub flag set (which I set using parted). The /boot partition has the boot and legacy_boot flags set (also set using parted). The /boot partition is formatted with ext4. I installed grub with the following commands:

grub-install --target=i386-pc --recheck /dev/sda
grub-mkconfig -o /boot/grub/grub.cfg;

Can anyone see anything wrong with my setup?

cfr · 2013-11-30 03:26:43

Can you post the output of gdisk -l /dev/sda?

It sounds as if you have too many boot flags set on the boot partition but it would be better to see the output. gdisk is a better choice for GPT than fdisk since the support in fdisk is relatively new and still, I think, somewhat experimental. gdisk, on the other hand, is designed for GPT.

Is that the exact error message you get? That is, are those the precise words?

What hardware are you on? Does your machine support EFI?

gsingh93 · 2013-11-30 03:58:29

Here are pictures of gdisk -l /dev/sda and parted /dev/sda print, since there's no way to copy and paste from the other machine:
https://dl-web.dropbox.com/get/Public/I … G2DzakPRBQ
https://dl-web.dropbox.com/get/Public/I … W_OxrfPqXQ

I don't get any error message actually. I just get a single white cursor blinking in the upper left corner. I'm fairly certain that means it can't boot, as originally I had network boot as the option right after booting from the hard drive, and it kept trying to PXE boot (meaning it skipped the hard drive option).

I originally had the legacy_boot flag on the /boot partition, but that didn't work, so I added on the boot flag.

What specific hardware do you need to know? I'm not sure what's relevant. I saw a UEFI setting in the BIOS but I left it disabled. I don't completely understand what the difference is or if there are any advantages to UEFI, but I don't think it's required to get GPT working, since I got it working on another machine without these problems.

cfr · 2013-11-30 04:09:01

gsingh93 wrote:

Here are pictures of gdisk -l /dev/sda and parted /dev/sda print, since there's no way to copy and paste from the other machine:

Why not? Can you not get an internet connection? If you can, just install wgetpaste or similar.

I don't get any error message actually. I just get a single white cursor blinking in the upper left corner. I'm fairly certain that means it can't boot, as originally I had network boot as the option right after booting from the hard drive, and it kept trying to PXE boot (meaning it skipped the hard drive option).

Well, presumably you know it can't boot. The question is why. So you get POST and then you immediately get the blinking cursor and nothing else? What happens if you try to boot via your machine's BIOS boot menu?

I originally had the legacy_boot flag on the /boot partition, but that didn't work, so I added on the boot flag.

Note that I'm not sure what this means. I don't know what fdisk does to GPT partitions now if you choose these options. (There is no "boot flag" in the GPT spec that I know of. parted uses the term for something which isn't a boot flag, though I forget what exactly. (Setting the type code on the BIOS boot partition maybe?)

What specific hardware do you need to know? I'm not sure what's relevant. I saw a UEFI setting in the BIOS but I left it disabled. I don't completely understand what the difference is or if there are any advantages to UEFI, but I don't think it's required to get GPT working, since I got it working on another machine without these problems.

It depends on your hardware. That's why I asked. Some firmware will not boot a GPT partitioned disk in legacy mode. Mine, for example. Others are quite happy to. There are some work arounds but whether they succeed or not is obviously firmware dependent. The name and version of your UEFI firmware and the vendor of your machine or motherboard might be useful. (Not to me, probably, but others may well know.) Probably it is a configuration error but be aware that it could be buggy firmware. (My machine boots GPT quite happily in UEFI mode - well, with a few serious caveats but it does work. Or legacy mode with MBR. But legacy + GPT just gets me "No operating system found". That's one reason I asked about the precise wording.)

EDIT: By the way, I can't view your dropbox files in any case. I just get complaints that I'm not logged in and shouldn't be there. wgetpaste or similar is definitely the way to go here if you have an internet connection. That is, boot to the live environment as you do to get the gdisk output, I assume, get the network working and install one of the CLI paste tools. (Or chroot and install it if you prefer. Doing it without chroot will obviously lose the tool when you reboot.)

Last edited by cfr (2013-11-30 04:13:01)

prabuselva · 2013-12-02 11:38:40

Hi gsingh93 ,

I converted my Arch from MBR partitioned disk to GPT partitioned disk a week ago... It works clean OOB....I dont know the reason for your boot failure.. As for as my laptop is concerned, I disabled the UEFI boot from my laptop and just used Legacy BIOS option. My Archlinux works perfectly with both UEFI+GPT as well as BIOS+GPT. The problem must be in your GPT First sector partitions. Make sure that your bios_grub partition is >= 1007KiB !!

also Make sure that u have disabled the UEFI as well as Secure boot in your BIOS?

Last edited by prabuselva (2013-12-02 11:39:05)

ajbibb · 2013-12-03 16:36:15

Intel BIOS by chance? In early November I did almost the exact same HD wipe, repartition and install to a couple of years old desktop with the exact same results. GPT will not work on some types of BIOS chips with certain Intel types (not all, just a few) being known not to work. On my machine I did see the Intel splash screen before the blinking white cursor so didn't even waste any more time seeing if I was indeed one of the lucky few and went back to MBR. If your BIOS is one of the few that does not work you can partition other drives in your box with GPT, only the boot drive has to be MBR.

CarlD · 2013-12-04 13:48:25

I recently (i.e. yesterday evening) installed Arch to my (intel i5) EFI laptop. in the process I converted what was an MBT table (previous ditro install) to GPT. If it helps, I can give an overview of what I did to get it working:

1. Used GParted to remove existing partitions, format to GPT, and create new partitions.

2. Used 4 partitions:

* SDA1: EFI (512MB - FAT 32 - flagged as Boot)
* SDA2: Root (50GB - EXt4)
* SDA3: Swap (2GB)
* SDA4: Home (900GB - Ext4)

Swap was sandwiched in the middle basically to help make the system run faster (i.e. less distance for the HD head to travel between Root and Swap).

3. Used GRUB2 + extra EFI programs for booting (as per wiki instructions: https://wiki.archlinux.org/index.php/Be … ide#GRUB_2).

The system boots and operates fine (secure boot disabled and in legacy mode). Should still work with MBR, though (it's that some UEFI systems apparently won't work unless GPT is used: https://wiki.archlinux.org/index.php/Un … _Partition).

Hope this helps.

srs5694 · 2013-12-07 01:32:49

I recommend you read the following two Web pages that I've written:

Reading these pages will give you a much better understanding of many issues that are related to your problems. My personal recommendation is to switch to EFI-mode booting. Although you might be able to get BIOS-mode booting to work, because your firmware supports EFI-mode booting, that way is likely to work better. Some EFIs make it hard to boot from a GPT disk in BIOS/CSM/legacy mode; and EFI-mode booting is often faster and has some other minor benefits.

That said, some EFIs are extremely buggy, which can make BIOS/CSM/legacy-mode booting easier; however, using GPT on such EFIs in BIOS/CSM/legacy mode can often be difficult, too, so you may end up having to switch to MBR partitioning.

Unfortunately, none of this is definite; part of the problem with EFIs is that there's so much model-to-model variability. If you get a good EFI, you'll do fine and have few problems; but a bad one can make it next to impossible to get anything to work.

Oh, and you do have an EFI, not a BIOS -- at least, not technically. (Many people, and even companies, use "BIOS" to refer to EFIs, but that's not really accurate.) Any firmware that has an "EFI" or "UEFI" option is an EFI.

Arch Linux

#1 2013-11-30 03:17:13

Arch won't boot with GPT

#2 2013-11-30 03:26:43

Re: Arch won't boot with GPT

#3 2013-11-30 03:58:29

Re: Arch won't boot with GPT

#4 2013-11-30 04:09:01

Re: Arch won't boot with GPT

#5 2013-12-02 11:38:40

Re: Arch won't boot with GPT

#6 2013-12-03 16:36:15

Re: Arch won't boot with GPT

#7 2013-12-04 13:48:25

Re: Arch won't boot with GPT

#8 2013-12-07 01:32:49

Re: Arch won't boot with GPT

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