GRUB Not Loading Arch Install

BMatt · 2012-08-23 21:49:44

I've been toying around with an Arch x86_64 Live Boot trying to get it installed on an external drive, and have run into a roadblock. I got it installed, but I think I may have messed up the GRUB install. I'm 99% certain I'm supposed to be using and EFI bootloader with bootloader, so I installed GRUB according to this: https://wiki.archlinux.org/index.php/GR … _systems_2 However, after I do all the configuration stuff from the Unofficial Beginners guide and reboot into the external drive, I get "error: file '/boot/grub/i386-pc/normal.mod' not found." Why would it be looking for an i386 file? Will I need to just delete GRUB and reinstall it via the liveboot?

EDIT- I suppose it wouldn't hurt to include some additional information. All the partitions are logical, sda5 is an ext4 root, sda6 is xfs /home, and sda7 is fat32 /boot/efi. sda7 has the boot flag enabled.

Last edited by BMatt (2012-08-23 22:09:01)

DSpider · 2012-08-24 04:35:36

Logical partitions means it's MBR-formatted and not GPT-formatted.

For UEFI boot, GPT is recommended.

https://wiki.archlinux.org/index.php/UE … n_in_Linux

Note: It is recommended to use always GPT for UEFI boot as some UEFI firmwares do not allow UEFI-MBR boot.

BMatt · 2012-08-24 20:39:32

I assume theres no way to set it up using GPT without totally wiping out the other partitions?

windscape · 2012-08-24 20:59:35

BMatt wrote:

I assume theres no way to set it up using GPT without totally wiping out the other partitions?

Actually, there are instructions to convert from GPT to MBR without data loss at a link mentioned on the GPT Wiki page here: https://wiki.archlinux.org/index.php/GP … MBR_to_GPT

I did this on my system and it worked fine, although I backed up my partitions first using fsarchiver and System Rescue CD. I also did not have any logical partitions on my system. I eventually switched back to MBR without data loss as well, to run an OS that didn't like dual booting with GPT.

BMatt · 2012-08-24 21:13:38

Ok, just some pre conversion jitters. I have two NTFS primary partitions, and three logical partitions. They should all be preserved when I open the disk in gdisk and write it?

BMatt · 2012-08-24 21:39:27

Ok, I went ahead with the conversion, but now when I boot to the drive, it simply says GRUB with a flashing prompt. Should the boot flag be on the / partition or the /boot/efi partition?

cfr · 2012-08-24 22:06:06

It should be on the EFI partition but whether or not it is a "boot" flag depends on which utility you're using. In parted, that's what it calls it. In gdisk it names it correctly, I think. But whatever it is called, it should be on the EFI partition.

To get it to boot, you also need to have booted in EFI mode and added the menu entry to the EFI boot menu as described in the wiki. grub-install does this for you but it only works if you are booted in EFI mode and have modprobed efivars. efibootmgr doesn't work otherwise.

Then again, I just realised you are getting GRUB so maybe that bit is OK. I'm not sure how the conversion process works but perhaps UUIDs get changed in the process?

Last edited by cfr (2012-08-24 22:08:00)

DSpider · 2012-08-25 06:00:24

Reinstall the bootloader.

AFAIK, GRUB doesn't care for boot flags and the information about which partition is bootable is stored in hidden sectors after the MBR, which have probably been replaced by the GPT (which shoots past the first 512 bytes).

https://wiki.archlinux.org/index.php/Be … bootloader

cfr · 2012-08-25 14:45:03

I think that's true for BIOS mode but not EFI mode. For EFI mode, it uses the EFI partition and I think this needs to be marked appropriately in the partition table though perhaps it will work even without that if you're lucky. But the official setup definitely requires the EFI partition to be marked appropriately. efibootmgr then gets used to create the grub entry in the EFI boot menu.

Here's the first line from gdisk -l on my machine:

   1            2048          976895   476.0 MiB   EF00  efi

"EF00" is the equivalent of the boot flag. Rather weirdly, this shows all my linux ext4 partitions as having type 0700 which is rather worrying...

Here's the output from efibootmgr:

BootCurrent: 000A
Timeout: 0 seconds
BootOrder: 000A,0007,0008,0005,0006,0009
Boot0000  Setup
Boot0001  Boot Menu
Boot0002  Diagnostic Splash
Boot0003  Rescue and Recovery
Boot0004  Startup Interrupt Menu
Boot0005* USB CD:
Boot0006* USB FDD
Boot0007* ATA HDD0:
Boot0008* USB HDD
Boot0009  PCI LAN
Boot000A* arch_grub

zeek · 2012-08-27 16:36:16

cfr wrote:

Rather weirdly, this shows all my linux ext4 partitions as having type 0700 which is rather worrying...

Not sure, but some insight into your query? What version of gdisk did you use when creating the partitions?
Link: http://www.rodsbooks.com/gdisk/walkthrough.html

Pertinent paragraph (after the 5th code block/output)

"The second partition, which will hold a Linux ext3 filesystem, receives the new (as of gdisk 0.7.2) 0x8300 type code. Prior to June of 2011, no official Linux filesystem GUID type code existed; Linux partitions typically took the same code as Windows partitions. This can cause problems, though, because Windows sees the Linux partitions as unformatted Windows partitions, and offers to format them—something you don't want to do! The new 0x8300 type code (or 0FC63DAF-8483-4772-8E79-3D69D8477DE4) avoids that problem, so I recommend you use it on Linux partitions."

Cheers

Edit: 0: gdisk version question re-phrased

Last edited by zeek (2012-08-27 17:21:17)

cfr · 2012-08-27 18:25:31

I created the partitions last November - probably using parted though I checked them all with gdisk. They definitely had type 8300 when I created them and more recently. I've changed them back now - it just seems weird that they had altered somehow. I can't think what I might have done to cause that. I did have to reinstall stuff from backup after a bad memory module caused filesystem corruption a few months ago. Maybe I accidentally did something then.

Arch Linux

#1 2012-08-23 21:49:44

GRUB Not Loading Arch Install

#2 2012-08-24 04:35:36

Re: GRUB Not Loading Arch Install

#3 2012-08-24 20:39:32

Re: GRUB Not Loading Arch Install

#4 2012-08-24 20:59:35

Re: GRUB Not Loading Arch Install

#5 2012-08-24 21:13:38

Re: GRUB Not Loading Arch Install

#6 2012-08-24 21:39:27

Re: GRUB Not Loading Arch Install

#7 2012-08-24 22:06:06

Re: GRUB Not Loading Arch Install

#8 2012-08-25 06:00:24

Re: GRUB Not Loading Arch Install

#9 2012-08-25 14:45:03

Re: GRUB Not Loading Arch Install

#10 2012-08-27 16:36:16

Re: GRUB Not Loading Arch Install

#11 2012-08-27 18:25:31

Re: GRUB Not Loading Arch Install

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