How To Modify Regions For Encrypted CPS2 ROMs?

[Jdurg]

Hey guys. It's been a while since I went and did any "ROM Hacking" of any kind, and for some reason my Google-fu is quite weak at the moment. I have just updated by CPS2-Multi with the key writing ability and am using the latest Smokemonster pack.

There are a few games which didn't come out in the US, but are available in Japan/Euro/Other regions. I would like to modify the region indicator bit within the program rom, but don't know where that bit lies, nor where to look in the various flash.xx files.

Would one of the kind folks here who understand how the files are setup for the multi-kit, and also how the regions are set within the main encrypted ROMs, guide me on how to do this? Any help would be greatly appreciated. Many thanks!

 

[Jdurg]

Anybody? I think Kuze stated in a separate thread that you could simply flip a bit to change region, but no description of how to do it was given. If changing the region of a game for use on the multi is a major breach of etiquette, then no worries.

I just have a list of five games that were not released in the USA region that I would like to switch to USA to see if they will still work. I'm just OCD about the start-up screens, etc.

 

[kuze]

Anybody? I think Kuze stated in a separate thread that you could simply flip a bit to change region, but no description of how to do it was given. If changing the region of a game for use on the multi is a major breach of etiquette, then no worries.

I just have a list of five games that were not released in the USA region that I would like to switch to USA to see if they will still work. I'm just OCD about the start-up screens, etc.

If you have a decrypted set for two regions of a given title with the same version string, you can use a hex editor to compare the program ROMs and find the offset where the region value is stored.

 

[Jdurg]

Awesome. Thank you. Will give that a try later on. If I don't have access to decrypted versions, does it mean it's a no-go?

 

[kuze]

Awesome. Thank you. Will give that a try later on. If I don't have access to encrypted versions, does it mean it's a no-go?

All encrypted sets are in MAME.

 

[Jdurg]

Ooops. I mean decrypted versions. Kind of an important typo there. :p

 

[kuze]

Decrypted sets can be found at cps2.avalaunch.net, but if they aren't there you would need to decrypt them first or maybe request the Avalaunch team process them for you.

 

[Jdurg]

Okay. Sweet. I was able to get Ring of Destruction region changed from Euro to USA by modifying the bit at C1 from 02 to 01 to make it USA. I understand that this will not work with all games, but that was still pretty neat to see. God I love this multi.