r/psxdev • u/Zestyclose_Reach_986 • 2d ago

Hex code editing

Hello guys first of all this is my first Reddit post so sorry if it’s shitty still learning my way around here.
My situation is: I have a PlayStation 2 with a modbo chip/opl from where I am playing monster hunter dos. I am trying to change the value of the machalite in the save files, and am just miserably failing and am looking for somebody who understands this sorcery better and is willing the help a poor soul out. I could provide the recent save files if there is somebody who could do it for me, would be greatly appreciated.

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u/khedoros 1d ago

When you compare the files, are the changes just here and there, or are the contents like wildly different? Is there any community-generated information out there describing the file format (data structures, offsets of different values, etc), or any obfuscation/encryption that might have been applied?

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u/lefsler 2d ago

What have you tried? Do you understand the format or have a table that explains it? Does it have a CRC that needs to be updated?

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u/Zestyclose_Reach_986 2d ago

I am not at all a programmer, don’t really know what I am doing here. I have extracted the save files onto a usb-stick using opl. I can open it and read the hex code but can’t like decode it.
Last thing I’ve tried was comparing two files one with 2 one with 1 machalite in my box.
I’m not sure which file even is the right one if it’s one of the play00bin ore the big main one

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u/lefsler 2d ago

Hex data is just a representation of the binary data. So the save has no metadata so you need to look online which byte represents what. That or make changes, save and diff, but that reverse engineering for experienced ppl is already hard, for you it's going to be a nightmare