Grub2 display problem

1. Changing Menu Resolutions

   If the user wishes to change the resolution of the GRUB 2 screen for image enhancement or general font size changes:
2. Set the desired resolution in /etc/default/grub
   • Change the value of GRUB_GFXMODE= (Example: GRUB_GFXMODE=800x600)
   • If unsure of what resolutions are available to GRUB 2 they can be displayed by typing vbeinfo in the GRUB 2 command line. The command line is accessed by typing "c" when the main GRUB 2 menu screen is displayed.
3. Select an image of the same proportions.
   • GRUB 1.99 - Place the image in the grub folder or add a GRUB_BACKGROUND entry in /etc/default/grub
   • GRUB 1.98 - Change the value of WALLPAPER in /etc/grub.d/05_debian_theme
   • GRUB 1.99 - Place the image in the grub folder or add a GRUB_BACKGROUND= entry in /etc/default/grub
   • If an image of the correct size is not used, the menu will not be positioned correctly.
   • Use the image editor of your choice to create/resize an image to the correct size.
   • The user may be able to view the image size via Properties in a file browser (check the Properties Image tab in Nautilus).
4. Run update-grub to update GRUB 2

Creating User Splash Images

GRUB 2's splash image management makes it easy to use a wide variety of splash images.

Resolution Settings

The images in the grub2-splashimages package are primarily 640x480 images.

GRUB 2 looks for a resolution setting in /etc/default/grub. If uncommented, the resolution is determined by this line:

• GRUB_GFXMODE=640x480

• If no setting is found in /etc/default/grub, GRUB 2 attempts to use the highest resolution possible. GRUB 2 may not be able to handle the same resolutions as the computer can once the operating system is booted.

Image Creation and Setup

In Ubuntu, refer to the Display in DASH or via the System, Preferences, Display menu for available monitor resolutions, or run vbeinfo in the GRUB 2 terminal to display the resolutions available it.

1. Determine the resolution you will use for the GRUB 2 splash image.
2. Create or resize any image to to the appropriate size.
   • GRUB 2 currently supports PNG, TGA, and 8-bit JPG/JPEG images.
   • The images should be RGB, non-indexed.
     • If using GIMP, naming the file with the applicable extension will save the file in the given format. Set the correct properties via the "Image > Mode" menu.
3. Make the applicable changes in the GRUB 2 configuration files:
   • /etc/default/grub: Uncomment the GRUB_GFXMODE=640x480 line and change the value if the resolution will be other than 640x480.
   • Add the GRUB 2 background image information to the configuration files(s) as discussed previously.
4. Run sudo update-grub to incorporate the changes into GRUB 2. 
    

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     https://help.ubuntu.com/community/Grub2/Displays#Changing_Menu_Resolutions