build/roms: support SeaGRUB *with menu enabled*

This is useful on desktops, where you want GRUB to
automatically start, but you still want access to the
GRUB menu, in the case where you rely on SeaBIOS to
execute the VGA ROM inside your graphics card.

Signed-off-by: Leah Rowe <leah@libreboot.org>

script/build/roms

@@ -398,8 +398,10 @@ build_grub_roms()
 			newrom="${romdir}/${payload1}_${board}_" && \
 			newrom="${newrom}${initmode}_${keymap}.rom"
 		x_ moverom "${tmpgrubrom}" "${newrom}"
-		[ "${payload_seabios_grubonly}" = "y" ] && \
+		if [ "${payload_seabios_grubonly}" = "y" ]; then
+			mkSeagrubRom "${tmpgrubrom}" "${newrom}"
 			mkSeabiosGrubonlyRom "${tmpgrubrom}" "${newrom}"
+		fi
 		x_ rm -f "${tmpgrubrom}"
 	done
 }
@@ -428,7 +430,7 @@ mkSeabiosRom() {
 }
 
 # SeaGRUB configuration
-mkSeabiosGrubonlyRom()
+mkSeagrubRom()
 {
 	_grubrom="${1}"
 	_newrom="${2}"
@@ -441,7 +443,17 @@ mkSeabiosGrubonlyRom()
 	    add -f "${tmpbootorder}" -n bootorder -t raw
 	x_ rm -f "${tmpbootorder}"
 
+	x_ moverom "${_grubrom}" "${_newrom%.rom}_grubfirst.rom"
+}
+
+# SeaGRUB, and disable the SeaBIOS menu (grub only)
+mkSeabiosGrubonlyRom()
+{
+	_grubrom="${1}"
+	_newrom="${2}"
+
 	x_ "${cbfstool}" "${_grubrom}" add-int -i 0 -n etc/show-boot-menu
+
 	x_ moverom "${_grubrom}" "${_newrom%.rom}_grubonly.rom"
 }