Ubuntu – What default fonts are used

Basically what you want to do is use the range operator to limit the characters that your new grub font contains. If you don't use the range operator then you're going to get all the glyphs including the erroneous or incorrect box elements from your target font.

For example:

grub-mkfont -s 16 --range=0x0-0x7f -o /boot/grub/grubfont.pf2 font.tty

Will generate a font with only ASCII characters, anything your font doesn't have should decay gracefully to the default font so boxes and arrows should come from the default. Please see this website for further information:

http://grub.enbug.org/gfxterm

To diagnose issues such as these, try the following:

1. Examine to see if its a nouveau driver vs nvidia issue - i.e. the yellow pixel observation could show a driver issue. Try installing the nvidia drivers i.e. ensure you are connected to the internet - run Administration - Hardware Drivers. If you are offered a restricted NVidia driver that is not activated, then try activating it. Once installed type the following to set up your display.

   gksudo nvidia-settings

2. Try rebuilding the ubuntu font cache through the following (i.e. may be the missing stuff is due to the fonts not being built or corrupted somehow)

   sudo fc-cache -v -f