Operating systems that support Multiboot
The following operating systems are known to support out-of-the-box the Multiboot specification to boot their kernels. This simplifies their boot process in machines with multiple operating systems installed because there is no need to chainload their native boot loaders (if any); GRUB is all that is required.
IMPORTANT: Some of the operating systems listed here are either partially or completely composed of proprietary software, or recommend proprietary software indirectly. This list is only for informative purposes about Multiboot, and inclussion in it does NOT imply our endorsement. Only operating systems that fully respect your freedom are endorsed by the GNU project. If you want to learn more about this, please see http://www.gnu.org/distros/free-distros.html.
Feel free to add any other operating system that supports Multiboot to the list below; just keep it sorted alphabetically.
BeginAgain, a component of OpenBIOS.
NetBSD since the 4.0 release.
The following is a list of Multiboot “OS kernels” that are actually bootloaders, i.e. they do not necessarily support loading a Multiboot OS kernel, but can be loaded from a Multiboot bootloader *as if they were* one, and then load their (legacy format) kernel:
GRUB 2 itself can be loaded by any Multiboot bootloader
MirBSD The /boot aka ldbsd.com loader (i386 only) can be loaded as Multiboot kernel, PXE/UNDI or COMBOOT module, and then can load MirBSD and OpenBSD kernels, GRUB-legacy, GRUB 2, bootsector files, or chainload partitions.
ReactOS The freeldr.sys bootloader can be directly loaded and run as a multiboot kernel
A few more examples can be found at: