In case you have a screen with high resolutions, a 4k screen for example, it is possible that GRUB is incredibly slow. If that is the case, the workaround is to edit the /etc/default/grub file, and add/replace the following line
GRUB_GFXMODE=1280x1024x32,auto
Then run “update-grub” to update the GRUB.
This will run GRUB in 1280x1024x32 resolution, which is the workaround for this problem.
Please make sure the resolutiion is support. The “auto” means that GRUB will fallback to auto detect in case the resolution isn’t supported.
