I had Ubuntu 14.04 (updated to 15.04) installed before and now have Xubuntu 14.04, both have the same issue. The grub menu is blank, as in there is no text, no sign that the grub is there aside from the 10 second timeout. In Ubuntu it was a purple screen that I got since the Ubuntu grub is pruple and now its black in Xubuntu. The os boots fine afterwards.
Macbook pro 8,1
GRUB_TERMINAL = console
from/etc/default/grub
http://askubuntu.com/questions/161297/why-does-my-screen-blank-out-for-the-duration-of-the-grub-boot-menu – Chintan Jun 03 '15 at 04:56