Reverting to previous kernel to avoid booting the new one that breaks my system

Question

I am on 14.04 and just did an update on one of my web servers. I am using the GUI. I ran the updates and it broke my VM.

I am new to Ubuntu and Linux in general so please bear with me.

I was able to get the VM to load by selecting a previous kernel on the boot loader.

My question is, how do I revert back to that kernel so that this VM does not boot into it every time the machine is restarted?

Solution 1

backup old version

sudo cp /etc/default/grub /etc/default/grub.backup

edit grub config file

gksudo gedit /etc/default/grub

#GRUB_DEFAULT=0
GRUB_DEFAULT="Advanced options for Ubuntu>Ubuntu, with Linux 3.16.0-50-generic"

Update prior line for the kernel you want to boot from

save, then

sudo update-grub

sudo reboot

Solution 2

The grub2 documentation refers to some useful settings that can be used to set the default boot option.

Edit /etc/default/grub (you need root privilege to do this) and change and/or add the following settings:

GRUB_DEFAULT=saved
GRUB_SAVEDEFAULT=true

and then run:

sudo update-grub

On the next reboot, select the kernel you want to boot from now on. The next reboot should boot from that selected kernel.