Enable grub menu UBUNTU

Enable grub menu: edit the /etc/default/grubĀ  file and change the GRUB_HIDDEN_TIMEOUT=0 GRUB_HIDDEN_TIMEOUT_QUIET=true to GRUB_HIDDEN_TIMEOUT=10 GRUB_HIDDEN_TIMEOUT_QUIET=false Save and call: sudo update-grub from a terminal, and reboot.