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Can you guys please help me use Grub Customizer to set an older version of the kernel 4.4.0 of Ubuntu 16.04 LTS as default when booting? I'm not using a dual boot system, and I have installed 4.4.8 kernel to help me solve the suspend problem, but it's draining my battery.

What do I have to do, I wouldn't want to f*** things up.

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Mookey
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2 Answers2

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Im not familiar with that program but if I want my computer to boot to a different kernel I just manually edit the grub file located at:

/etc/default/grub

Look for 

GRUB_DEFAULT=0 (or whatever your default is set too)

Change that line to the kernel you want loaded ... looking at your list there it looks like 0 would be the standard 4.4.8 and 3 would be the standard 4.4.0

Once you have selected the one you want save the file (you will have to edit the file in root) and then use the command:

sudo update-grub

now when you reboot it should default to which ever kernel you have it set too. When you do update-grub it should print out a list of kernels found ... just verify that you chose the right one .. not sure if I was misreading the list that program shows .. but just be aware that the numbers do start at 0 so the first entry it prints is 0 not 1

John Orion
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  • I'm kind of unsure whether this will work... When I open the etc/default/grub I see GRUB_DEFAULT=0, but I'm unsure what number my kernel is. Is there a way I could do this with the customizer? Or double-check which number my older kernel is? More importantly, could I just remove the latest kernel, and will the boot automatically go to the older one the default one? – Mookey Apr 28 '16 at 07:38
  • OK, I installed the program and well ... I don't trust it. Basically the way it seems to change it is to click on the General settings tab and changing the default entry from (first entry) to the kernel but .... I checked the grub file and it printed the title there instead of the numeric value .. not sure if that works or if that would cause grub to fail.... but judging by the list it shows me and your list shown I can tell you if you want the 4.4.0 kernel ... you would want to set GRUB_DEFAULT=3 and then it will default to that kernel – John Orion Apr 28 '16 at 23:47
  • remember to run sudo update-grub after saving the grub file or it will not set the change – John Orion Apr 29 '16 at 00:18
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Ok .. Decided to give it Grub Customizer a try on a VM box so I didn't screw anything up. I was able to change the default kernel without any issues. Here is how I did it.

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In the General settings tab I clicked the pulldown for predefined. It listed all the kernels available. I chose the 3.19.0-58-generic and clicked save ... I rebooted into that kernel. Even though I was worried about it putting the name instead of the numeric value .. it seems to work fine.

So you would have no problems doing the same thing .. just choose the generic one for the kernel you want to use .. not the (upstart) or (recovery mode)

In your case .. the pulldown would probably say either Ubuntu, with Linux 4.4.0-21-generic or Advanced options for Ubuntu>Ubuntu, with Linux 4.4.0-21-generic

John Orion
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