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I installed a mainline kernel for testing purposes. I would like to set grub to boot from the older kernel by default.

I know I can set the GRUB_DEFAULT=0 setting for the first page of grub but how do I set it to boot by default from one kernel in the second page (Advanced page)?

I would prefer doing this without installing other software (ex. grub-customizer).

Related Questions:
How do I set Windows to boot as the default in the boot loader?
How do I change the grub boot order?

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  • 3
    @belacqua: It is not a duplicate. This question is about setting an older kernel that is not present in grub's first page of options as default.
    – To Do
    Nov 13, 2012 at 13:14
  • It seems like this case should be covered in the earlier questions, even if the method needs to be update for 12.10, older kernels, etc..
    – belacqua
    Nov 13, 2012 at 15:26
  • 3
    The question's use case is different, and the answer is very specific in a way that doesn't apply to the other claimed duplicates. I came here to solve this particular problem; not to change the boot order; nor to boot Windows. +1 for "not a duplicate".
    – Robie Basak
    Mar 16, 2015 at 14:09

6 Answers 6

Reset to default
180

First, make a backup copy of /etc/default/grub. If something goes wrong, you can easily revert to the known-good copy.

sudo cp /etc/default/grub /etc/default/grub.bak

Then edit the file using the text editor of your choice (e.g. gedit, etc.).

sudo -H gedit /etc/default/grub

Find the line that contains GRUB_DEFAULT - this is what you'll want to edit to set the default. You must know the full name of the kernel you want - e.g. Ubuntu, with Linux 3.13.0-53-generic - along with the full name of the "advanced menu" - e.g. Advanced options for Ubuntu.

You then combine those two strings with > and set GRUB_DEFAULT to them as: GRUB_DEFAULT="Advanced options for Ubuntu>Ubuntu, with Linux 3.13.0-53-generic" (including quotes).

Save it, then build the updated grub menu.

sudo update-grub

See also: GNU GRUB Manual 2.02 or more specifically section 15.1.0 on setting the default.

Note: There is a method utilizing numbers to access kernels and menus but this is not recommended as it is unreliable when kernel updates occur.

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  • 27
    Using a numeric value can be problematic when updates occur. It's better to use a text default, ie: GRUB_DEFAULT="Previous Linux versions>Ubuntu, with Linux 3.2.0-18-generic"
    – Bealer
    Jul 4, 2013 at 16:45
  • 36
    One can use sudo grub-mkconfig | less to see all of the possible options
    – Nitz
    Feb 17, 2015 at 20:55
  • 9
    This is a good solution, but even better is to open a /boot/grub/grub.cfg and there you will see all the manuentry and all the submenus. If you edit them, you can easy set the default ones, even change the Titles of the options in the grub list when restarting a computer.
    – Aleks
    Apr 21, 2015 at 21:03
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    It is definitely useful to examine /boot/grub/grub.cfg to determine the exact names to use. But do not change this file as it will be automatically regenerated by update-grub, including on updating packages.
    – Robie Basak
    May 19, 2015 at 16:36
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    The formatting for GRUB_DEFAULT is slightly outdated (since at least Ubuntu 14.04.2). Running update-grub I encountered a warning: Please don't use old title Previous Linux versions>Ubuntu, with Linux 3.13.0-53-generic for GRUB_DEFAULT, use Advanced options for Ubuntu>Ubuntu, with Linux 3.13.0-53-generic (for versions before 2.00) or gnulinux-advanced-b0ce60c3-184c-453b-af59-419b56a2584f>gnulinux-3.13.0-53-generic-advanced-b0ce60c3-184c-453b-af59-419b56a2584f (for 2.00 or later)
    – Wumms
    Jul 3, 2015 at 21:32
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The best solution for me was to set (in /etc/default/grub):

 GRUB_DEFAULT=saved
 GRUB_SAVEDEFAULT=true

With this settings the last selected value is kept for the next boot. If you have a new kernel you don't have to edit your config.

Don't forget to re-run sudo update-grub

The solution is from reading: info grub-mkconfig

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  • 9
    This is awesome
    – Mephisto
    Jan 31, 2018 at 17:58
  • are you sure about the semicolon (;) at the end of the lines?!?
    – DJCrashdummy
    Mar 18, 2018 at 8:54
  • I can not look into my computer where I used it in this moment, but you are right ";" seems to be wrong or unnecessary!
    – Martin T.
    Mar 21, 2018 at 10:36
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Now that an Advanced menu is default in Ubuntu, you'll need to select it before the kernel you want using the > character.

Set e.g.:

GRUB_DEFAULT="1>7"

in /etc/default/grub and re-run sudo update-grub.

It is important to note that for the GRUB menu entries numbering starts with 0. Therefore the 1 above points to the Advanced menu. As a precaution, you may want to initially set GRUB_TIMEOUT=5. Some may be unable to access GRUB by hitting a key at boot time. This is a safety net in case you accidentally point to something like Memory test instead. It is also necessary to include the above numbers in quotes. It will not work otherwise.

I tested on 16.04 LTS.

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4
  • Works in Debian too.
    – Lawrence D'Oliveiro
    Mar 16, 2018 at 2:36
  • I find this answer very useful, as after a kernel update it still points to the newest kernel. in my setup for example it is 1>0, meaning: advanced-first listing (is always the newest kernel). my system sometime stopped to automatically update the 0 entry of grub with the newest kernel, so i use this method.
    – Peter Fleix
    Oct 13, 2018 at 9:25
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    Unsure if this has been mentioned - but you can mix the numbers + string to select the Advanced menu AND the kernel version you want. eg GRUB_DEFAULT="1>gnulinux-5.4.0-121-generic-advanced-e17a595e-18f3-45e3-8f22-e0d1005fbae1" Currently the newest kernel is borked. This gives the confidence it will pick the right version each time on reboot. So this gets me out of a hole for the moment.
    – jsonUK
    Jul 15, 2022 at 20:59
  • @jsonUK I think I tested the strings versions when preparing this answer and had trouble making them work. Granted, it's been six years :) Thanks for pointing it out.
    – sarnold
    Jul 18, 2022 at 20:49
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To be able to set which boot option to use as default you need to know what there is... so:

To display the menu entries without actually booting, try something like:

$ lsb_release -s -rdc
Ubuntu 16.04.4 LTS
16.04
xenial

$ update-grub --version
grub-mkconfig (GRUB) 2.02~beta2-36ubuntu3.17

$ grep -Ei 'submenu|menuentry ' /boot/grub/grub.cfg | sed -re "s/(.? )'([^']+)'.*/\1 \2/"
menuentry  Ubuntu
submenu  Advanced options for Ubuntu
    menuentry  Ubuntu, with Linux 4.4.0-34-generic
    menuentry  Ubuntu, with Linux 4.4.0-34-generic (upstart)
    menuentry  Ubuntu, with Linux 4.4.0-34-generic (recovery mode)
menuentry  System setup
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  • 4
    sed -nre "/submenu|menuentry/s/(.? )'([^']+)'.*/\1 \2/p" < /boot/grub/grub.cfg - The same effect using only sed
    – Hannu
    Jan 26, 2020 at 9:34
  • Verified to still work on 20.04.
    – Hannu
    Aug 29, 2020 at 15:43
  • Second time; Verified to still work on 20.04 / kernel 5.13.0-35-generic
    – Hannu
    Mar 18, 2022 at 15:58
  • works in 22.10, with 5.15 and 5.19
    – cipricus
    Oct 26, 2022 at 14:30
3

When I have initially posted this I haven't noticed the OP's specific requirement not to propose grub-customizer... Sorry.

For what it's worth I'll leave it here but also confirm that the best solution is indeed the most up-voted one HERE, with variables that can be found as indicated in THIS complementary answer.

In order to do it with a GUI, I use Grub Customizer (I'm in Mint but that doesn't count here).

The simplest and most direct way (thanks @eMKi for the suggestion in comment) — best suited for a permanent setting, in General Settings > default entry > predifined, simply select the desired kernel in the drop-down list.

enter image description here

Or, in case one needs the "previous booted entry" to be the one selected (might be useful in dual boot with Windows when doing an Windows update that requires restart, for example) — keeping the Advanced options in the grub list in case the default list is changed within Grub Customizer:

enter image description here

under General settings select the default entry: previous booted entry.

enter image description here

Then, reboot, and during boot select the "Advanced options" entry in the grub list:

enter image description here

and select the older kernel

enter image description here

On the next reboot, the "Advanced options" item will be the one selected by default in the grub list and the last selected kernel from under there will be booted (without opening the full list of kernels).

In case Windows is used, or other option in the grub list, remember to re-do the previous procedure.

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  • 1
    Hi, you could also just select a default boot entry from the list of available options in the 'Predefined' line. It depends, if you wish to have it selected permanently then that would be a good option. If you like to choose different entries then your way is better. Thanks for the GUI solution.
    – eMKi
    Jan 11, 2021 at 19:17
  • @eMKi - I was not aware of that basic setting, which should be the most obvious. So, I added that to my answer.
    – cipricus
    Jan 12, 2021 at 9:19
0

In order to change the default kernel to load you can set kernel boot priority in /etc/default/grub file.

First Take a backup of /etc/default/grub before making any changes.

While booting if you don't see Grub boot loader at all, you have to make it visible, for that change these 2 lines in Grub as

GRUB_TIMEOUT_STYLE=menu
GRUB_TIMEOUT=10

Now while loading you should be able to see the grub menu.

To change the kernel loading priority you have to make a change in GRUB_DEFAULT as the default setting it is set as

GRUB_DEFAULT=0

check the serial number of the kernel that you want to set as default, the numbering is 0 indexed, change the index accordingly. eg if you want to load the 6th entry from the top, you have to set the index as 5.

GRUB_DEFAULT=5

Now update grub using sudo update-grub and restart.

Check this YouTube video to make grub visible.

Check this Ubuntu help page to know about GRUB_DEFAULT.

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1
  • This is not helpful for the described problem: the desired kernel is hidden inside the "Advanced options" sub-menu list. The "advanced" item in the main menu list can be selected by order with GRUB_DEFAULT but that is not the solution unless the desired kernel is first in the sub-menu. How do you select an item that is second or third in the "advanced" sub-menu?
    – cipricus
    Oct 26, 2022 at 14:20

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