Install grub2-themes-ubuntu-mate by entering the following commands in the terminal:
sudo apt update sudo apt install grub2-themes-ubuntu-mate
Description:
GRand Unified Bootloader, version 2 (ubuntu-mate theme)
This is the ubuntu-mate theme for GRUB's graphical menu.
Homepage: https://github.com/nadrimajstor/grub2-themes-ubuntu-mate
Version: 0.3.7
Section: universe/admin