What would it take to mod an ISO?

Discussion in 'PSP - Hacking & Homebrew' started by TheDarkOne, Aug 5, 2013.

  1. TheDarkOne
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    TheDarkOne Member

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    I searched google real quick and found nothing about modding ISO's or CSO's. Has anybody ever attempted it or is it not possible yet? I would like to start with making very minor retextures in a game I have and have it run like normal.
     
  2. Isaac

    Isaac American

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    Here? Right here? What about, say... over there?
    It wouldn't be that hard, just open it up it umdgen, find the files you want to edit (They may use a strange format) extract, then reimport, the files and save the iso.
     
  3. TheDarkOne
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    TheDarkOne Member

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    Really? I thought it would be a nightmarish project that would take a minimum of one week just to break into it. Huh. Thanks I'll look at some tutorials on how to use it.
     
  4. FAST6191

    FAST6191 Techromancer

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    Without looking it up I think the option to hack PSP games has technically been around longer than the DS. Despite that though PSP hacking is still in its infancy for reasons I am not entirely sure about.

    The eboot.pbp file is what holds the binary, though like any binary it can include non instruction related code.
    There are various formats commonly seen in PSP isos. Being a bit more powerful than other handhelds there are a few games that use common formats seen on the PC.
    Emulator wise there is not a lot, it has got a lot better since various keys were leaked but still not a patch on the likes of the better NES or GBA stuff. This is OK as there are various methods to debug the PSP at runtime.

    There are some people doing good work in PSP hacking
    http://gbatemp.net/threads/final-fantasy-type-0-romhacking.340183/ and http://skybladecloud.wordpress.com/ being a jumping off point ( http://skybladecloud.wordpress.com/miscellany-2/tales-of-destiny-2-psp-compression-system/ if you want to get a bit more technical right away).

    You might also be able to pull something from
    http://akatranslations.wikispaces.com/PSP+Translations
     
    jastolze likes this.
  5. TheDarkOne
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    TheDarkOne Member

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    That's very good information thanks. To be honest I'm way over my head, I know basic hexadecimal and binary but not enough to understand the point of converting those translations from numbers to other numbers. I just see it as separate numbers and don't see any meaning to it. Yeah time to spend some time learning all the terms.
     
  6. Cyberdrive

    Cyberdrive GBAtemp Regular

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    PSP ISOs have just a standard ISO 9660 file system without any extensions or other file systems, so anything that claims to work with ISO will work with this as well. I personally use Apache 3 Preview by Sonix for my PSP ISO modding needs, although I'd recommend an older Apache 2 instead. This tool replaces any file with its modified version that has smaller or equal size without rebuilding the whole image;
    if the new file is larger but still fits in the same number of 2048-byte sectors as the original file, it's possible to replace it and correct the file size in the file system manually using a hex editor (e.g.WinHex) to avoid rebuilding the whole ISO;
    if the new file is even larger, you'll have to rebuild the ISO, and UMDGen has practically become a scene standard for this.
    CSO is just a compressed ISO: uncompress - edit as above - recompress.