mbootpack (Multiboot kernel and modules)

This is a tool that takes a multiboot kernel and modules (e.g. a Xen VMM,
linux kernel and initrd), and packages them up as a single file that looks
like a bzImage linux kernel. The aim is to allow you to boot multiboot
kernels (in particular, Xen) using bootloaders that don't support multiboot
(i.e. pretty much anything except GRUB and SYSLINUX). This is, as you might
expect, pretty grim stuff, involving lots of lovely 16-bit real-mode code.