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Nicolas
Asked: 2019-08-26 08:53:37 +0800 CST

update-grub warning regarding GRUB_DEFAULT title name

  • 772

When setting GRUB_DEFAULT to:

Ubuntu 18.04.1 LTS (18.04) (auf /dev/nvme0n1p2)

update-grub emits a warning (3 times) that I should not use this "old title", but should use one of the following, depending on my "version".

For versions pre 2.00:

Advanced options for Ubuntu 18.04.1 LTS (18.04) (auf /dev/nvme0n1p2)>Ubuntu 18.04.1 LTS (18.04) (auf /dev/nvme0n1p2)

For versions 2.00 or higher:

gnulinux-advanced-c40111ac-c9cb-43b2-b72b-e6d86975cd57>gnulinux---c40111ac-c9cb-43b2-b72b-e6d86975cd57

I assumed that this warning means the grub version with "version". So I picked the latter format, as my grub is 2.02-2ubuntu8.

But it didn't worked. When changing back to the "old title" it works again.

Warnung: Bitte verwenden Sie nicht den alten Titel
»Ubuntu 18.04.1 LTS (18.04) (auf /dev/nvme0n1p2)« für GRUB_DEFAULT, verwenden Sie
»Advanced options for Ubuntu 18.04.1 LTS (18.04) (auf /dev/nvme0n1p2)>Ubuntu 18.04.1 LTS (18.04) (auf /dev/nvme0n1p2)« (für Versionen vor 2.00) oder
»gnulinux-advanced-c40111ac-c9cb-43b2-b72b-e6d86975cd57>gnulinux---c40111ac-c9cb-43b2-b72b-e6d86975cd57« (für 2.00 oder neuer)

Why shouldn't I use the normal "old" title and what would be the correct title then? Or should I ignore this message?

System informations:

Linux htpc7even3 4.15.0-58-generic #64-Ubuntu SMP Tue Aug 6 11:12:41 UTC 2019 x86_64 x86_64 x86_64 GNU/Linux
No LSB modules are available.
Distributor ID: Ubuntu
Description:    Ubuntu 18.04.1 LTS
Release:    18.04
Codename:   bionic
grub2

4 Answers

  1. The Grub-manual states:

    Previously it was documented the way to use entry title. While this still works it’s not recommended since titles often contain unstable device names and may be translated

    Your entry-title contains a device-name (/dev/nvme0n1p2). Devices names may change if you remove or add a drive or reconnect the existing drive to a different slot.

    In such a case the menu-entry-titles in /boot/grub/grub.cfg would be updated when you run 'update-grub' and this would make the default (which remains the same) invalid. Thus you get a warning, you can still use it if you want and knowing what you're doing, never add or remove drives.

    It's recommended to use the menu-entry-ID instead which does not contain a device name but the UUID of the partition you want to boot from, that's much more stable.

    You don't need to use the two-level-identifier. I just copied the identifier of my first menu-entry from /boot/grub/grub.cfg and set

    GRUB_DEFAULT='gnulinux-simple-06a41c79-a7ff-4fd2-86eb-fb4f510bf31a'

    and then ran sudo update-grub which finished silently (no error, no warning), also no problems during reboot.

    • 3

  2. Easiest to edit /etc/default/grub like this...

    sudo -H gedit /etc/default/grub

    GRUB_DEFAULT=saved
GRUB_SAVEDEFAULT=true

    sudo update-grub

    This way, GRUB remembers the last OS you selected, and will continue to reboot to that same OS until you select a different OS.

    Much simpler than trying to match textual names, or using raw numbers.

    • 2

  3. What's I've always done on this is to match exactly what shows up in the "Advanced Options for Ubuntu" Grub menu. So if it looks like this:

    enter image description here

    I use

    GRUB_DEFAULT="Advanced options for Ubuntu>Ubuntu, with Linux 5.0.0-25-generic"

    This produces no errors or warnings when sudo update-grub is run.

    • 1

  4. In Ubuntu (or any derivative) you can simply install grub-customizer (it is in the repositories) and open it. Then "General settings" and in "predefined" choose the kernel you want to start with. Save. That's it.

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