If you don't already have FlashBIOS on the chip then you can't use a BIOS to put it on there. (chick and egg scenario) But, since your box is already modded you can use a couple different apps to flash your chip. The EvoX dashboard has a flash utility, but it only works like FlashBIOS. Starts writing at bank 1, so if you would want to flash bank 2 you would need to build a 1MB BIOS and allow bank 1 to get overwritten as well. FlashX is a nice utility that lets you pick what area of the chip you want to flash. So if you want to drop FlashBIOS in bank 2 without touching bank 1, you can do it. If you use FlashX and get confused by the fact that it shows 4 banks on screen, read the 2 banks/4 banks link in my sig.
-Whoopin'