OSDev.org

I've been using GRUB to load my OS and have used grub-mkrescue to make an ISO. The only problem is that on the GRUB boot screen it displays:
GNU GRUB version 1.99-21ubuntu3.14
How do I get rid of the ubuntu?

By compiling your own version of GRUB from source code instead of using the one supplied by your Ubuntu distro. However, I see no real reason for this - the one supplied by Ubuntu should work fine, and if it does not work for you, then the problem is probably not GRUB.