Grub is the most commonly used bootloader in Linux system. When you boot up your computer, the default Grub screen comes with a black background and white text. If that is fine with you, then this tutorial is not for you.
On the other hand, if you wish to beautify it with your favorite image, this tutorial covers 5 simple steps that you can follow to create and install your custom Grub splash theme.
1. Design your own image
Using any image editor, create an image that is of dimension 640×480. Keep your image simple and not too colorful. As Grub only supports 14-bit of color, if you use a colorful image, there will be a great loss of color and result in a distorted image later when we convert it to Grub compatible format. The best choice is to keep it simple, plain but nice. You can check out gnome-look.org for some inspiration.
Save the image (preferably in jpg or png format, but it doesn’t really matter).
2. Convert image to Grub compatible format
Open your image with GIMP (“Applications -> Graphics -> GIMP”). Go to “Image -> Mode” and select “Indexed”.
In the popup window, make sure that the “Generate optimum palette” option is checked. Change the “Maximum number of colors” to 14.
At the bottom, set the “Color dithering” option to “None.”
Go to “File –> Save As” and save the image with a .xpm extension.
3. Zipped up the image
In your Nautilus (“Places -> Home Folder”), navigate to the folder where you save the Grub image. Right-click on the image and select “Create Archive”.
In the window that popup, change the archive type to “.gz.” Click “Create.”
4. Install StartUp Manager
Install StartUp Manager via your terminal, here’s the command:
5. Installing Grub theme
Open StartUp Manager (“System -> Administration -> StartUp Manager”). On the “Boot options” tab, check the box “Show bootloader menu”.
Go to the “Appearance” tab.
Click on the “Manage bootloader themes” button. In the next window, click “Add” to add new theme. Navigate to the folder where you save your Grub image and select the zipped file. Click “Close.”
Back to the StartUp Manager screen, select the Grub theme from the dropdown bar and check the box “use background image for bootloader menu”.
Restart the computer. You should see your custom Grub image in action now.
Image credit: -= Treviño =-