Hacking GCN Converting stubborn save game regions (MP, SCII, ED)

[egparadigm]

Hi all,

I had some success yesterday hex editing European save games to work on the USA games, e.g. Super Smash Bros Brawl, Billy Hatcher. I did this by simply editing the opening line of the .gci files to replace P (Europe) with E (USA). It also seemed to make a difference that the name of the gci file should also match this.

But I have found certain games uncooperative. Specifically:

• Metroid Prime (MP)
• Soul Calibur II (SCII)
• Eternal Darkness: Sanity's Requiem (ED)

Of these I have played around most with MP and SCII. I have been able to remove save slots from MP for example and then transplant them into another European save. So it appears I am able to identify the part of the hex that represents a save slot. However I am unable to get these to work when transplanting over to the USA save game, possibly because I can't identify the right place to put them in the other region save. It could simply be that these two save formats are completely non-compatible and, from my web searches it certainly seems to suggest that MP has incompatible cross-region saves.

I am curious particularly with SCII. Firstly, it has quite a lot of my playtime contained within (whereas with MP it could simply be exchanged for a downloadable 100% save). Secondly, I have compared the structure of the hex using HxD and, it seems to be largely the same. There are a few differences (besides the E/P bit) in the header:

Europe:

USA:

... then it's exactly the same for the middle section.

Only the last block differs. This is the block that contains the player data in the European version. I have successfully transplanted this data from my own save game to a freshly generated one in Dolphin.

The last block is the same length and position in both regions, starting at offset 00004040, ending in offset 00008030. This makes me think that it may be possible to transplant the data from one region to another. Unfortunately it just comes up corrupted if I try transplanting the hex across from Europe to USA .gci.

I am just posting this in a last ditch effort. Have any of you ever successfully converted regions for any of the above games and, if so, how? Otherwise any ideas are welcome. If not, never mind!

Thanks for your attention.

 

[master801]

Saves may be hashed like Animal Crossing does.

 

[egparadigm]

Hi and thanks for your reply. Would you care to elaborate? Any way around hashing?

In regards to Animal Crossing I was able to use GCMM to move my save file from the memory card that came with the game to my MemCard Pro GC. However in that case it was just moving the save rather than editing the region.

 

[master801]

Hi and thanks for your reply. Would you care to elaborate? Any way around hashing?

In regards to Animal Crossing I was able to use GCMM to move my save file from the memory card that came with the game to my MemCard Pro GC. However in that case it was just moving the save rather than editing the region.

You'll have to disassemble the game and figure out the hashing method yourself.

By the way, it turns out Metroid Prime really is hashing.

https://github.com/PrimeDecomp/prime/blob/main/src/MetroidPrime/CMemoryCardDriver.cpp#L211

 

[egparadigm]

OK I take it then (as I am no disassembler) that this is not within the realms of possibility, until or unless someone decompiles these games. Thanks for the info and link.