MAMEWorld Forums - News - Re: DU: Medal no Tatsujin

> We got Medal no Tatsujin. It's System 10. I'm not sure if System 10 games will ever
> be emulated though, if the custom chips have data and can't be read.
>
> http://smitdogg.mameworld.info/du/Medal_no_Tatsujin.jpg

That's a misconception. Till now, the only games found to be using that last NAND block protection are gunbalina/ptblank3. Your dump from gunbalina had other additional incorrect blocks scattered through the file but, as it's clear that the encrypted block is exactly identical to the one in ptblank3, redumping it is probably useless. All the other type2 games listed in the driver (https://github.com/mamedev/mame/blob/master/src/mame/drivers/namcos10.cpp ) were properly decrypted last year; some details can be read here:
https://github.com/mamedev/mame/blob/master/src/mame/machine/ns10crypt.cpp

Some of the decryptions work on the fly in current MAME (up to five, IIRC); others haven't been properly hooked up due to requiring further research on a funny protection for triggering the decryption. Still, the decrypted content have been available for other devs from last august.

Beside gunbalina/ptblank3, the only other game in the current driver which haven't been decrypted is mrdrilr2/mrdrilr2a, which is a type1 and whose encryption seems to use a previous iteration of the same idea.

I had access to a partial dump from a TNT game provided by Guru and it clearly used a different layout of the encrypted region, and probably different libraries within it (which isn't surprising, given the use of the CD on those boards), but they are probably doable too.

So, in sum, what is deterring the progress in NS10 is no longer the encryption but, well, a lack of time/interest of capable devs.

Edited: Oh,now that I read more carefully the posts, you were talking about the CPLD; well, the CPLD is thought to embody the crypto logic, and probably could have additional logic (the glue logic needed to bypass the triggering protection I briefly mentioned could be one of them), but it probably don't contain data. The confirmed data problem is the (apparently for protection purposes) problem with the last NAND block in gunbalina/ptblank3. That last block doesn't contain encrypted information, but the encryption seems to work differently than in other type2 games, so my bet is that whatever is in there is used to provide the nonlinear behaviour that other games are deriving otherwise.

Edited by Andreas Naive (02/01/16 11:27 AM)