Netrunner - grub and grub-customizer


in the normal installation is also grub-customizer embedded.

So, if I choose grub-customizer with different colours and a picture for the boot-menu, I get

  • a black screen with white letters, no other colours
  • a reduced menu, so I selected in grub-customizer (ok)
  • no picture, I selected

during running up the system, than I get the selected picture in grub-customizer, but in a minimised form.

Is there any way to solve that?
If it is not comfortable to do that in Netrunner than I will delete grub-custmizer again.
Who can get colours for the Netrunner-grub-menu?
Directly in the /etc/default/grub dataset?