OpenBIOS is an IEEE 1275-1994 compliant firmware which can also be used as a coreboot payload.
$ svn co svn://openbios.org/openbios/openbios-devel $ cd openbios-devel $ config/scripts/switch-arch x86 $ make
The file obj-x86/openbios-builtin.elf is your final OpenBIOS payload to be used with coreboot. Alternatively, you can use obj-x86/openbios-plain.elf, which does not contain a built-in dictionary and is thus a lot smaller.
| I, the copyright holder of this work, hereby release it into the public domain. This applies worldwide.
In case this is not legally possible: