Simple answer, yes. Boot into your bios and format the mem card (seeing as you legally dumped ur bios and stuff, and you own a dreamcast, you should know how to format the memory card)
If you have the bios dont' have any CD in the disk drive or the virtual drive that Chankast reads. Then you just goto start run like you were going to play a game. Then it should take you to the bios menu and stuff. There you can use the memory card manager and format the memory card for use.