Generate Font for GRUB
sudo grub-mkfont --output=/boot/grub/fonts/DejaVuSansMono24.pf2 \
--size=24 /usr/share/fonts/truetype/dejavu/DejaVuSansMono.ttf
sudo vim /etc/default/grub
add to top
GRUB_FONT=/boot/grub/fonts/DejaVuSansMono24.pf2
Update Grub
sudo update-grub
