I try boot PC without payload. In make menuconfig have selected this options:
 
Devices:
    Run VGA Option ROMs
    Run non-VGA Option ROMs
VGA BIOS -> Add a VGA BIOS image
    (SC4-F400.BIN)
    (5333,8a20)
PXE ROM:
    (gpxe.rom) or (rtspxe_m.lom)
    (10ec,8139)
 
PC boot and have only flash cursor '_' on screen and in debug have this message:
 
"CBFS: File 'pci10ec,8139.rom' is of type 50, but we requested 30."
 
How make gpxe.rom type 30 or how change request type to 50?
 
Does possible insert Legacy Option ROM (ISA) ?