Use seabios ROM if you want to use an add-on GPU. seabios_withgrub and seabios_grubfirst are also available.
this is forked from the "libre" branch in osboot, which is itself a libre, deblobbed fork of osboot, a blobbed up fork of libreboot libreboot needed to be purged clean. this is the new libreboot development repository. the old one has been abandoned