[coreboot] Coreboot Payload.

Hi,

I am using "GRUB-2" as a direct payload for a Denverton based implementation.
Is it possible to invoke a payload which is programmed as a separate Image (not as a part of cbfs coreboot image) within a BOOT flash ?
If not, then what are the areas do we need to modify in a state-machine to implement the same ?

Thanks in advance,
Nitin.