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How to lock grub2 default selection?

rated 0 times [ 1] [ 0] / answers: 1 / hits: 1516 / 2 Years ago, wed, march 9, 2022, 4:07:19

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 Years ago

answered 2 Years ago rowbris · Accepted Answer

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"