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This morning linux-image-3.5.0-26-generic was installed during a software update. On my laptop this proved to be unusable after 10 minutes. I changed to linux-image-3.5.0-24-generic and all seems fine. I have updated the default grub2 selection to the 24-generic. How can I lock the default grub selection to this value so subsequent updates don't overwrite and make themselves default?

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3 Answers 3

Reset to default
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how to lock a kernel grub entry

With a bit of command line trickery, you can get the default of grub to always be a particular grub entry no matter when a new kernel is installed or updated.

In a terminal type:

fgrep menuentry /boot/grub/grub.cfg

This will display all your grub entries - for example

enter image description here

Highlight the entry you want to default to - for example 'Ubuntu, with Linux 3.2.0-31' in the screen-shot. Right click and choose copy

Type

gksu gedit /etc/default/grub

Change the entry

GRUB_DEFAULT=0

to

GRUB_DEFAULT='2>Ubuntu, with Linux 3.2.0-31-generic'

i.e. paste the entry you want (including the quotes) BUT PREFIX with the text 2>

Save, then type

sudo update-grub

The text 2> is important because this informs Grub that the entry to boot from exists in the sub-menu called "Previous Linux entries"

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you can use this tool, Grub Customizer. To download, Open terminal and type:

sudo add-apt-repository ppa:danielrichter2007/grub-customizer [enter]

sudo apt-get update [enter]

sudo apt-get install grub-customizer [enter]

Open dash and search grub customizer, and run it. Edit configuration with this tool.it's easy . Go to General Settings to edit the default, time boot etc

enter image description here

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  • Thanks - I installed that and was able to edit the default entry so to the version I desired. I did NOT notice how to "lock" the default so that new kernels wouldn't overwrite and make themselves default
    – pfeiffep
    Feb 28, 2013 at 20:34
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I just searched and found this file:

/etc/default/grub

Command grub-mkconfig (or update-grub) uses this file for default values. Try editing line GRUB_DEFAULT=0 to GRUB_DEFAULT=1.

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  • Thats only good until the next kernel upgrade happens.
    – guntbert
    Feb 28, 2013 at 17:26
  • I want to insure that on subsequent kernel updates grub2 default selection REMAINS on whatever I've modified in the grub2 menu. Or is it possible to have a dual boot config based on kernel level?
    – pfeiffep
    Feb 28, 2013 at 17:32
  • Oh, I understand. This way Kernel3 would take Kernel2 place and default=1 would point to Kernel 2, instead of Kernel1. But it seems GRUB_DEFAULT can be set to a string. I don't have the exact answer, but I thinks it's here: link.
    – Balgerda
    Feb 28, 2013 at 17:44

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