Sometimes, VESA buffer cannot properly auto-detect the resolution of your screen during boot-up. You may set the VGA/VESA resolution there using grub. To fix it, open /etc/default/grub
in an editor
# Adjust the following lines: # see also https://askubuntu.com/a/609523 # GRUB_GFXMODE=1280x1024x32 # GRUB_GFXPAYLOAD_LINUX=keep sudo update-grub