I am running a self-managed VPS, hosted by a local (Australian) company; recently I've upgraded in quick succession from 14.04 to 16.04 to 18.04. But through all these upgrades, although I've collected plenty of new linux kernel images, the grub default has remained on the old 3.13 kernel from Ubuntu 14.04. Using update-grub simply adds kernel lines to grub.conf which is a symlink to menu.lst; it doesn't change the default.

I'm a bit nervous to make sweeping changes by hand to the menu.lst file in case I end up with an unbootable machine - I can't use a rescue disk as I don't have physical access to it.

What's my best option here?

  • Sounds like you need to reinstall grub if it isn't updating the kernel being used. I don't remember seeing menu.1st file in a long time – Jeremy31 Aug 8 '18 at 21:30

Issue the dist upgrade to install the latest kernel.

$ sudo apt-get update
$ sudo apt-get dist-upgrade

Keep the old kernels, don't delete them so that you can still selection under the advance menu in the grub boot manager if you need to go back. No need to manually modifying the grub boot manager file.


You might just need to edit the following line in /etc/default/grub:


This determines the default OS/kernel to boot. The value or string after the equals sign might be set to the specific OS/kernel that your system keeps defaulting to.

Setting this to a numerical value will default what loads in your GRUB list on boot, with 0 as the first option. This is meant to be the default value of the grub file, allowing the system to boot from the top-most entry in the list.

Assuming the kernel you want to use is at the top of the list, you can then change your grub file so that the line shows:


Once saved, run:

sudo update-grub

If, however, the OS/kernel you want to boot is, say, the 4th entry down in your list, you would instead use:


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