grub2 background color on Ubuntu

• 17.10 and later:
  

  sudo -H gedit /usr/share/plymouth/themes/default.grub
  

And change the grub background color as you want, in my case I change grub background to black (0,0,0)

if background_color 0,0,0 ; then
   clear
fi

Then, update grub

sudo update-grub


https://askubuntu.com/questions/47488/how-to-change-the-purple-background-color-in-grub

Nice teal that stands out from Win and Ubuntu alike: rgb(0, 123, 96)