Well, I don't know about the Mega Drives with a BIOS. My cart spits out exactly what it has been programmed with, so if the header of your ROM file is ok in the first place, I don't see a reason why it shouldn't work. I've only tested the cart with an old style Mega Drive, but when I can get my hands on a Mega Drive 2, I'll check this one, too.
What exactly do you mean with mask ROMs ?
> Thanks for the time,info and input on this project
You're welcome :)
> Sam
/chn