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A right way to change default kernel?

asked 2015-11-20 16:13:54 -0600

evb0110 gravatar image

updated 2015-11-20 16:14:30 -0600

I installed Fedora 22 several weeks ago and some time later updated to 23. Now when I boot I have 5 or 6 available kernels. The default kernel has the word "debug" in its name and as it seems works worse than 23's kernel without "debug". Since I'm a novice I'm looking for a simple and secure solution:

1) How could I change the default kernel to boot without "debug"?

2) Should I delete some of the kernels? What is the "right" way to do it?

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answered 2015-11-20 17:35:16 -0600

sergiomb gravatar image

Open /etc/default/grub and ensure this line exists:


and ensure this line not exists:


or ensure this line exists:



grep -P "submenu|^menuentry" /boot/grub2/grub.cfg | cut -d "'" -f2

grub2-mkconfig -o /boot/grub2/grub.cfg

grub2-set-default "<submenu title><menu entry title>"
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What does "<submenu title=""><menu entry="" title="">" mean? I think I know what one of these is but what is the second?

skomra gravatar imageskomra ( 2016-08-23 16:29:30 -0600 )edit

when you got sub menus if not in use GRUB_DISABLE_SUBMENU=true

sergiomb gravatar imagesergiomb ( 2016-08-24 23:24:05 -0600 )edit

answered 2017-07-12 11:38:30 -0600

mmartinez gravatar image

@skomra example of your question:

sudo grub2-set-default 4.8.6-300.fc25.x86_64

4.8.6-300.fc25.x86_64 = <submenu title=""><menu entry="" title="">

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Asked: 2015-11-20 16:13:54 -0600

Seen: 9,112 times

Last updated: Jul 12 '17