HOWTO: Set framebuffers for higher resolution in Debian based servers ( command line only )
Posted: 22. May 2017, 16:43# edit /etc/default/grub
Uncomment: #GRUB_GFXMODE=640x480
Modify it to required resolution: GRUB_GFXMODE=1024x768
Add the following: GRUB_GFXPAYLOAD_LINUX=keep
Save, exit, and run update-grub
Edit "/etc/modprobe.d/fbdev-blacklist.conf" and add vboxvideo
Reboot
Uncomment: #GRUB_GFXMODE=640x480
Modify it to required resolution: GRUB_GFXMODE=1024x768
Add the following: GRUB_GFXPAYLOAD_LINUX=keep
Save, exit, and run update-grub
Edit "/etc/modprobe.d/fbdev-blacklist.conf" and add vboxvideo
Reboot