DEVOPS: Repair the GRUB Bootloader to Boot Ubuntu - maple-dev-team/docs GitHub Wiki

If GRUB is not loading, then Ubuntu won't boot. Fortunately, you can repair GRUB using the Ubuntu installation media. Restart the computer with the disc inserted and wait for it to load up.

Again, you may need to change the boot order, as described above. Make a note of the boot order before you change it!

With the installation media booted into the Live environment, confirm you have a network connection and then open a Terminal. Enter:

sudo apt-add-repository ppa:yannubuntu/boot-repair sudo apt update sudo apt install -y boot-repair boot-repair