Users that use Proprietary Nvidia Drivers have problems with low resolution and low colour Plymouth boot.

To fix this You need to change some stuff in Grub file.

  • Step 1

You must edit the /etc/default/grub file.

Open a terminal and paste this:

$ sudo gedit /etc/default/grub

On line #18, uncomment (uncomment = remove the “#” in front of the line “#GRUB_GFXMODE=640×480” and change the resolution to whatever you want (in my particular case, I changed it to 1680×1050). Here is how it should look:

GRUB_GFXMODE=1680×1050

  • Step 2

edit the /etc/grub.d/00_header file.

$ sudo gedit /etc/grub.d/00_header

And find the following line: “gfxmode=${GRUB_GFXMODE}” (it’s line 103 on my computer) and under it, paste this:

set gfxpayload=keep

  • Step 3

update Grub 2:

To update the GRUB, simply run the following command:

$ sudo update-grub

Once you complete the above steps, restart the computer and you should see the nice Plymouth screen.

Source: sucka.net and ubuntuforums.org