[Help] How to make a save editor for 3ds games?

Discussion in '3DS - ROM Hacking, Translations and Utilities' started by Princess Emily, Jun 14, 2016.

  1. Princess Emily
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    Princess Emily Smiles innocently...

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    Aug 19, 2015
    Hi guys? Can anybody tutor me how to make a save editor? I wanna make one for Etrian Odyssey Untold because there's not one yet.
    What resources/programs should I get?

    For now I have a 3ds with homebrew. What else do I need?
     
  2. Princess Emily
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    Princess Emily Smiles innocently...

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  3. DarkIrata

    DarkIrata GBAtemp Fan

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    You should know a programming language.
    • C# is a easy to use language for this. (Use any IDE you like)
    • A HEX File reader like HXD to find the differences.
    • Any way to dumb the Save from the Game.
    • MUCH.. MUUHUUHUUCH patience.

    // Wubs. posted to soon.

    1. Start Game, find the value you want to edit.
    2. Dumb your save.
    3. Start Game, change value, save.
    4. Dumb your save.
    5. *Repeat to get a faster result (unnecessary)
    6. Look for the position in the save dumb (OFFSET) of the value.
    7. Make it possible to change value by your C# Application
    8. ???
    9. PROFIT
     
    Last edited by DarkIrata, Jun 16, 2016
  4. vozer

    vozer Member

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    You have to learn how to decrypt and encrypt your game save first
     
  5. Princess Emily
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    Princess Emily Smiles innocently...

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    Dumb
    my save? Do you mean dump?
     
  6. DarkIrata

    DarkIrata GBAtemp Fan

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    oh yeah sorry, should't write at work. :D
     
  7. acea

    acea Newbie

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    If you just want to edit the save file, all you need to do is dump a few savefiles with variations in the interested parameter only, then find the offset.

    Based on save file I have and what I remember from the game,
    Character data: 18C and on (starting with Fafnir); skills are lumped somewhere in the mid-end and retire/level information is near the end from what I can gather
    Ingredients: A6E5-A73F (all of the ingredients are lumped together; set everything to 63 to make all 99)
    Grimoires: 2770-758F (length = 32; beginning is misc. info like traded, etc followed by name, and actual add-on/skill/level are at the end).

    So on and so forth. If you can write a program to find the offsets and edit the value, that's the editor right there. Finding what value is what is more or less a trial-and-error. 3DS-native hex editor may be easier to find those.