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Miscellaneous Forums => Scripting and Reverse Engineering => Topic started by: Cyberman on 2003-01-06 14:51:09

Title: FF7 PSX CRC calculation region
Post by: Cyberman on 2003-01-06 14:51:09

Hmmm I'm porting Jenova (well it's more like rewritting Jenova but I digress) to a DLL for editing PSX memcards, Qhimm you have a clue what region of the card the CRC calculation is over?  I've diddled a while and it's got me stumped.. I've tried from just past the CRC word to message speed
This doesn't seem to work (File Ruined error).  I assume you haven't messed with the PSX version, but the CRC calculation is identical (that might be assuming a lot LOL).

Cyb

Title: FF7 PSX CRC calculation region
Post by: Cyberman on 2003-01-09 05:21:21

Ok.. I have the range right but I think the calculation is might be wrong for the PSX.  If I make no alterations of the data it comes up with the identical CRC.  I haven't seen the CRC stored twice.. so now I'm left with.. look ma no brains.. or I donno.

I perform the CRC from 2 beyond the CRC variable in the record to the end of the 7 bytes after the message speed indication byte.  If I alter anything I get 'file ruined' if I don't it calculates the CRC exactly right.  So what am I missing here, is there a second check it uses somewhere? Or do I need to finish my structured file hacking tool first? ;)

Cyb