Some analysis on Mii extdata

Discussion in '3DS - ROM Hacking, Translations and Utilities' started by Jhyrachy, Jan 3, 2015.

  1. Jhyrachy

    Jhyrachy GBAtemp Regular

    Jul 25, 2011
    first of all, thanks for reading this post, i'm not an hacker or an expert, just an hobbyst and all the analysis i have done in this thread are just my supposition, without any warranty or pretention to be true.
    I want to thanks MrCheeze for passing me the extdata dumping tool who allowed to dump the data

    First thing i have done, was to create a "Test" Mii, that you can scan with this QRCode:
    It's a complete default Mii, i only changed it's Birthday to be on the 01/01 because the field was blank previusly.

    Then, I dumped the extdata and I opened them using an hexeditor.
    The relevant part is here:
    It does not look so good, so take some screenshoots:

    In my understanding, the Mii has 3 fields
    First one is the Mii's Name, 10 characters long, 20 bytes
    Second one are the Mii's data, 26 characters long
    Third one is the creator's name,10 characters long, 20 bytes (i cutted out extra empty spaces)

    Now let's look at the 3ds Mii creator customization possibility, I found them HERE

    These are a lot of options, especially because they are stuffed in 26 characters and half of them looks empty too!

    Sadly, i have no idea how to handle this kind of data, I hope that these information could be usefull for someone smarter then me.

    I'll do more test, especially working changing some variables and looking how it modify the data, but i'm not too optimistic.

    Anyway, thanks for reading and sorry for my bad English!
  2. Cyan

    Cyan GBATemp's lurking knight

    Global Moderator
    Oct 27, 2002
    Engine room, learning
    Name's size are 10 (using 2 bytes, probably UTF16 for japanese characters).
    the mii data probably works like the one on Wii, there are editors for Wii version so you can find existing informations on Mii format.
    3DS adds move options/visuals.

    Are you sure it starts by Mii's name?
    on Wii, the format starts by Mii's data (sex, birthday, fav colors, fav)
    3dbrew says the QRCode has "Birthday (4bit-day,5bit-month), Sex, Shirt, ?? " before the Mii's name.
  3. Jhyrachy

    Jhyrachy GBAtemp Regular

    Jul 25, 2011
    I corrected the lenght!
    I'll do more research!