@Psionic Roshambo, Go with a custom BIOS chip. It can allow you to play games region free and re-enable Mil-CD support. They can also run debug executables from the Katana dev kit.
@K3Nv2, The Dreamcast format is different to Windows executables. In this case, the main executable is "1ST_BOOT.BIN" and is either signed for a debug kit or retail console, and is usually scrambled.
I played all regions with either patching the games directly or a boot disk wasn't too hard even shrank some games to fit on normal CDRs lol that was a bit harder