rmco2003
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« on: November 24, 2006, 06:34:25 am » |
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I've recently been looking into hacking the GBA game "Card Captor Sakura: Sakura Card-hen Sakura Card to Tomodachi" for the GBA. I've found that the game uses standard LZ77 compression for most graphics apart from the font, which is uncompressed and located at the end of the rom. The text I'm not so sure about, I've tried replacing the Japanese font with english characters and relative searching for the jibberish, but that's not produced any results. I've tried searching with wildcards like "A*B*C*" and still nothing, this leaves me to wonder if the text either has a really weird table file, or is compressed.
I've tried going through logs in VBA and decompressing whatever the game decompresses and taking a look, but most of it's graphics, and I think one or two blocks aren't, but I've tried relative searching inside them for text too and ended up with nothing.
Can someone give me some hints?
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Spikeman
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« Reply #1 on: November 24, 2006, 11:30:22 pm » |
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Seeing as the graphics are all compressed, the text probably is too. I'm not so good with compression, but maybe you could try corruption to find a piece of the text in the game and then change stuff around to figure out the compression scheme.
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rmco2003
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« Reply #2 on: November 25, 2006, 05:06:25 am » |
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I used Corrupster and got results when I corrupted around the 890000 to 900000 mark, but I'm not sure if what I'm corrupting is text, or graphics. Instead of loading the text and the rest of the graphics, it loads one sprite then pauses. It still plays music and sound effects, so I'm not really sure what's happening.  |
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Spikeman
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« Reply #3 on: November 25, 2006, 05:27:01 am » |
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Start narrowing down the range of corruption until the game works but the text is messed up. Then look around that area in the ROM.
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rmco2003
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« Reply #4 on: November 25, 2006, 05:30:26 am » |
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Well I've been narrowing it down and I think between the range of 880000 to 900000 there's control codes or something, because when I corrupt with random data in that area the game really messes up, starts the intro and then crashes.
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Spikeman
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« Reply #5 on: November 25, 2006, 05:41:16 am » |
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Then it's probably not in that area.. if you think it is try narrowing it down even further, until it doesn't crash. I'm not exactly a pro at corruption so hopefully someone who has a good amount of experience with it will post something.
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rmco2003
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« Reply #6 on: November 25, 2006, 05:51:56 am » |
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*sigh* corruption doesn't seem to be working out too well... I've tried broad ranges, I guess I'm going to have to step through the rom in really small chunks to be able to find the text without causing major crashes.
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Spikeman
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« Reply #7 on: November 25, 2006, 06:09:51 am » |
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Yeah that's the basic idea. The corrupter that's worked best for me is ROM Corrupter by DWEdit, because you can automatically try range after range. I looked through the database on documents about corruption but I couldn't really find any.  \ |
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rmco2003
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« Reply #8 on: November 25, 2006, 06:18:09 am » |
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hmm that program tells me it's having problems accessing files, not sure what that's about  |
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Spikeman
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« Reply #9 on: November 25, 2006, 06:40:10 am » |
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You'll need to have the ROM and the emulator in the same directory. It's a pain, but it works fine. Make sure you don't have them in different folders.
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rmco2003
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« Reply #10 on: December 02, 2006, 10:02:48 am » |
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I've submitted a help wanted request since I can't seem to locate the text, when I have some spare time I'll try smaller ranges of corruption.
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labmaster
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« Reply #11 on: December 02, 2006, 06:21:54 pm » |
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Looks like 16-bit uncompressed. One of the strings from the intro starts at 08F45E3A.
edit: this is the bit of dialogue I'm referring to.
[attachment deleted by admin]
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« Last Edit: December 02, 2006, 06:29:45 pm by labmaster »
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rmco2003
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« Reply #12 on: December 04, 2006, 07:24:09 am » |
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Thanks for the help labmaster how did you find it? |
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labmaster
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« Reply #13 on: December 04, 2006, 04:50:11 pm » |
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Debugger  |
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rmco2003
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« Reply #14 on: December 04, 2006, 05:32:34 pm » |
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Did you do logging? I only logged SWI information, and I'd like to know what you did so that I can do the same things for other projects |
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