After a day of struggling with bricked firmwares.... I finally ditched FreeDOS. I went with SystemRescueCd distro and burnt coreboot precompiled firmware under the folder /gigabyte_ma78gm/ and the firmware WORKED! But now I am stuck with funny firmware quirks (Windows XP crashing when booting halfway, almost to the point the video card driver is loaded, right after "GIVEIO.SYS" driver is being loaded), even though it loaded Linux CD fine. I guess I should try and ditch PS/2 mouse as it may probably be the cause of strange behavior - I will be using USB mouse / keyboard as well. I am happy with this firmware otherwise. And, the backup BIOS didn't even try to intercept the Linux kernel in the firmware from loading. Thankfully. I will eventually decide to recompile or "submit" the additional payloads such as EFI and memtest86+ as those software will be needed in the future, after I learn more of its capabilities.