4.1.2 Load another boot loader to boot unsupported operating systems
If you want to boot an unsupported operating system (e.g. Windows 95),
chain-load a boot loader for the operating system. Normally, the boot
loader is embedded in the boot sector of the partition on which
the operating system is installed.
Set GRUB's root device to the partition by the command
rootnoverify (see rootnoverify):
grub> rootnoverify (hd0,0)
Set the active flag in the partition using the command
makeactive1 (see makeactive):
Load the boot loader with the command chainloader
grub> chainloader +1
`+1' indicates that GRUB should read one sector from the start of
the partition. The complete description about this syntax can be found
in Block list syntax.