[request] first 4 mystery bytes in save data file

Discussion in '3DS - ROM Hacking, Translations and Utilities' started by bunny_gg, Feb 18, 2016.

  1. bunny_gg
    OP

    bunny_gg Advanced Member

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    Jan 20, 2016
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    I just exported save data of Project X zone (US) and I found the structure of save data quite clear: one part for weapon (0/1 bitmap), one part for item (quantity bitmap) and one part for characters ( exp, equipment, ...). It is easy to modify these but it displays save data corrupted after save data file being imported.
    I found first 4 bytes always changing in different save data files but I don't know the rule of how to generate them (exchanging two bytes in save data file doesn't work). Anyone has clue about these 4 bytes?

    Always failed to upload save data file and screenprint. Let me try again.

    I attach two save data here for reference. Difference is that I just unequipped weapon of one character in the second data and of course, timestamp is different.
    save data 1

    save data two
     
    Last edited by bunny_gg, Feb 18, 2016
  2. MissingNO123

    MissingNO123 Jigglypuff

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    hell
    Probably a checksum. You'd have to figure out how the game calculates it in order to generate your own.

    EDIT: It may also be the secure NAND value, which SVDT can get around.
     
  3. bunny_gg
    OP

    bunny_gg Advanced Member

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    Jan 20, 2016
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    the question is just about how to calculate...

    I just used SVDT to export and import the sav. I know SVDT can fix secure NAND problem but it doesn't work for this one.
    Another clue is that SVDT goes into debug mode with this game (same with animal crossing - new leaf), so I don't know if secure NAND step is skipped in this mode.I checked it is different. This game seems have no secure NAND.
     
    Last edited by bunny_gg, Feb 19, 2016