Comment 68 for bug 1863434

I ran into the same problem, and found the solution. Initially in grub2 the configuration is set to GRUB_GFXMODE=auto. On several systems grub seems to be unable to autodetect the proper resolution.
(In grub console "videoinfo" returned no (!) output on my system.) After altering to GRUB_GFXMODE=1280x800 which is the known resolution of my screen, yours may differ of course, my lovely bootmenu (don't forget to run update-grub after altering the config file) was visible again.

Formerly grub's default configuration seemed to be GRUB_TERMINAL= console, which now has been commented out. That leads to a nice output (as grub themes are supported) if it works. If not, it leads into the dark...