Arch Linux

illusixn

Member

Registered: 2020-01-20

Posts: 2

no arch entry in grub after updating grub from ubuntu, ubuntu hangs

The machine I tried to install Arch onto was already dual booting Windows and Ubuntu. When I got to the disk partitioning portion of the guide, there was an existing EFI partition so I later mounted it to /mnt/boot. After this point, I had no problems following rest of the installation guide.
I didn't bother installing grub because I figured I could update grub from Ubuntu. After doing so and rebooting, I found there was no entry for Arch. I tried to boot Ubuntu to try to fix the issue with grub, but it just hangs on a purple screen. I can boot Windows perfectly fine. I would post error messages, but I this is the only problem I've run into thus far. Is this situation salvageable?

Possible solution?
Boot the installation media and completely wipe the drive containing Ubuntu and Arch. Install Arch as I did before, but this time installing grub. Install Ubuntu (only so I have the option to use something I'm used to until I'm more comfortable with Arch). Boot into the Arch install and make sure grub is configured correctly to detect Ubuntu. - I do have a question about this, though: When I say "completely wipe the drive", would this also include the EFI partition that is already present?

I apologize if this seems like a stupid post, but any and all help/suggestions are welcome. Thank you in advance.

loqs

Member

Registered: 2014-03-06

Posts: 17,372

Re: no arch entry in grub after updating grub from ubuntu, ubuntu hangs

Arch is probably not detected due to the lack of https://git.archlinux.org/svntogit/pack … kages/grub
You could create a custom entry based on GRUB#GNU/Linux.

armoredkitten

Member

Registered: 2019-10-31

Posts: 15

Re: no arch entry in grub after updating grub from ubuntu, ubuntu hangs

When you updated Grub in Ubuntu, did you have the Arch partition mounted first? Grub won't be able to detect it unless it is mounted.

As for the issue of Ubuntu hanging, I'd recommend booting from a LiveUSB (of either Ubuntu or Arch, whichever you prefer) and inspecting your journal logs from there. You'd need to provide more details to properly troubleshoot the issue, but this isn't an Ubuntu support forum, so you're better off finding help for that elsewhere.

Either way, I suspect fixing the issue will take some investigation, but shouldn't require wiping the drive! Figure out a fix to boot to Ubuntu, then try running grub-mkconfig again with the Arch partition mounted.

Head_on_a_Stick

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From: London

Registered: 2014-02-20

Posts: 7,732

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Re: no arch entry in grub after updating grub from ubuntu, ubuntu hangs

there was an existing EFI partition so I later mounted it to /mnt/boot

Did you format the ESP at any point?

Note that you only need to mount the ESP under /boot if you intend to use systemd-boot or direct EFI_STUB booting.

I tried to boot Ubuntu to try to fix the issue with grub, but it just hangs on a purple screen.

If you drop to a GRUB command line what does this command say:

set

^ That should list all of the settings for you to check.

Is this situation salvageable?

Of course

Possible solution?

As this is the Arch forums I would advise you to load up an Arch live ISO image, mount the root partition & ESP then (arch-)chroot into the system and install and configure the bootloader from there.

The Debian/Ubuntu grub-mkconfig version has trouble with Arch systems if the processor µcode is installed because they can't deal with multiple options for the initrd line.

Grub won't be able to detect it unless it is mounted.

^ This is not correct, somebody needs to edit the wiki page.

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illusixn

Member

Registered: 2020-01-20

Posts: 2

Re: no arch entry in grub after updating grub from ubuntu, ubuntu hangs

Trying to process all the replies and get some clarification before starting:

When you updated Grub in Ubuntu, did you have the Arch partition mounted first?

The Arch partition was not mounted, but according to Head_on_a_Stick, this shouldn't have been a problem and the wiki needs to be edited.

I'd recommend booting from a LiveUSB (of either Ubuntu or Arch, whichever you prefer) and inspecting your journal logs from there.

Something like journalctl -b should suffice for this, correct?

Did you format the ESP at any point?

Note that you only need to mount the ESP under /boot if you intend to use systemd-boot or direct EFI_STUB booting.

I didn't do anything (explicitly) to the ESP besides mounting it under /boot. I read mounting under /boot simplifies things, but I guess not.

I would advise you to load up an Arch live ISO image, mount the root partition & ESP then (arch-)chroot into the system and install and configure the bootloader from there.

So should I remove /boot, but this time mount the ESP under /efi? Would installing the bootloader from inside Arch cause conflicts with the bootloader already installed by Ubuntu?
(sorry if formatting is bad, very new to this forum)

Last edited by illusixn (2020-01-20 21:12:27)

Head_on_a_Stick

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From: London

Registered: 2014-02-20

Posts: 7,732

Website

Re: no arch entry in grub after updating grub from ubuntu, ubuntu hangs

So should I remove /boot, but this time mount the ESP under /efi?

Just keep the ESP under /boot, it's not a problem as such and we should try to keep things as simple as possible while we work through this.

Would installing the bootloader from inside Arch cause conflicts with the bootloader already installed by Ubuntu?

No, UEFI is pretty flexible in that respect. The Ubuntu EFI stuff should have it's own directory and Arch won't touch that unless you declare the --bootloader-id option as "ubuntu" (or whatever the directory is called).

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armoredkitten

Member

Registered: 2019-10-31

Posts: 15

Re: no arch entry in grub after updating grub from ubuntu, ubuntu hangs

^ This is not correct, somebody needs to edit the wiki page.

Ahh, sorry, apologies for propagating the misinformation! I could swear I've had issues with os-prober detecting Linux installs in the past that were corrected by mounting the partition. But perhaps that is just my faulty memory combined with an error in the wiki...

Head_on_a_Stick

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From: London

Registered: 2014-02-20

Posts: 7,732

Website

Re: no arch entry in grub after updating grub from ubuntu, ubuntu hangs

^ This is not correct, somebody needs to edit the wiki page.

Ahh, sorry, apologies for propagating the misinformation!

Actually it should be me apologising to you because I've just double-checked from my lesser-spotted Arch box and grub-mkconfig does indeed seem to require that the other partitions be mounted. I can claim it must have changed since I tried it last but that's just me trying to save face.

@OP: sorry for the misinformation.

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