Recently i bought me an new led monitor, a Samsung 27″ LED S27A850T. Using this with my old BenQ, i finally could enjoy dual screen at home. Much to my girlfriends happiness i can add;) Anyway, at first, my crowded Ubuntu grub bootmenu wouldn’t show up anymore, Although, it booted the default OS after a couple of seconds. WTF i thought, i wanted to see the bootmenu. So, after some DuckDuckGo:ing (i.e. googling:) i found some commands that would do the trick for me. And maybe for you if you have similar problems.
1. Open the grub config file as sudo user in a texteditor .i.e. sudo gedit /etc/default/grub
2. Change the GRUB_GFXMODE to a videoresolution you think your monitor can handle, maybe GRUB_GFXMODE=800×600 . PS no hashtags before the command.
3. Add GRUB_GFXPAYLOAD_LINUX=keep after this in the file. It’s for keeping the same resolution in the Grub command console.
4. Save file, and then, to finalize the settings, do a sudo updategrub
Reboot, and you should hopefully see the bootmenu again. Please, retry with other resolutions otherwise i.e. GRUB_GFXMODE=1024×768, and so on, if it doesn’t work for you at first.