Halo,
if you need the Boot option, you can extract the option ROM from the old mainboard BIOS - direct from chip or from BIOS file that you can recive over internet. Use cbrom for the old BIOS, if it's from Award (the file call NCR in file name. This file you can add with AMIbcp to new BIOS file and flash this new created file into your FLASH ROM
Good luck
bye, Gerald