Mega Drive Unlicensed Game Emulation Notes

From Sega Retro

TODO: Is there a better category? And I have to add everything =P

Unlike official Mega Drive games, unlicensed games usually have copy protection schemes, SRAM mapping oddities, or other hardware quirks that emulator authors should take note of if they want their emulators to work with these games. sha1sums of dumps to watch out for are given.

All Realtec Games

TODO: wikify this

Affected ROMs:

All Realtec games use a custom mapper format documented by TascoDLX.

Ya Se Chuan Shuo

Affected ROMs:

  • "Imperial Dynasty" version: presently undumped
  • "The Legend of Arthur" version: 8fe0806427e123717ba20478ab1410c25fa942e6

The Data East/Side Pocket driver stolen from High Seas Havoc used in this game is slightly modified; an add from Z80 RAM to a register (TODO) is used. If this instruction is not emulated correctly, the play song routine will load invalid music and eventually crash.

Furthermore, the Z80 sound driver presumably expects that the uppermost 32KB of ROM (from $1F8000) be mirrored at $400000. This needs to be confirmed.

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