GRUB2 is an upgraded version of GRUB. It has a lot of improvements such as scripting support including conditional statements and functions, dynamic module loading, rescue mode, etc. GRUB2 is the default boot loader and manager since Ubuntu version 9.0 (Karmic Koala).
Here I concretely present how to customize boot menu of GRUB2. First we can edit the file
/etc/default/grub. The parameters can be studied from the link as I have just mentioned above. Then we run the command
update-grub to update the file
I think that the solution of this issue is not really hard if we understand mechanism and structure of boot manager.
See more details from the following links: