What is the pinout on the bottom? None of the pictures really show it. I would guess that it may be a gameboy cartridge dumper over printer port interface. -doulomb
They were the same cards that worked with the MGD - I think they were just marked "Doctor GB Card", and the original one was 4M, but later they made 16M and 64M versions. Later on (after Bung got sued by Nintendo) they were being sold (possibly only the 64M one) as "Mr Flash" - but it was exactly the same hardware. They used to be as common as dirt around here, but I haven't seen any of them for a long time. Edit: And one other thing is that you should never hot-socket those Bung flash cards - they have a Bung custom chip on them and it's very easy to blow it up by doing that.