Jeremy Evers


by Jeremy on April 15th, 2007

fatassMany years ago I made a Fast Tracker II clone for the Gameboy Color called Fatass. It was coded in pure z80 assembly, and was used to create music for several videogames.

I originally imagined myself writing entire albums with this thing on my travels.

Download it here: Fatass

Download the z80 source code here: Fatass z80 source code

You will need a gameboy color or gameboy advance emulator, or a flash system to use this.

Press select to get to the menu, from there you can access help, the file system, etc. Load some example tunes from rom to see what it can do. There’s even a version of a Big Brother song in there…

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11 Responses to ' Fatass '

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  1. baseck said,

    on February 22nd, 2011 at 8:38 pm

    the tracker looks amazing. i’ve been trying to load it onto a bleep bloop non usb cartridge with the usb transferer. every time i try to load it onto the cartridge it says: >Bad file size.

    any ideas why? i would love to use this. thanks!

  2. Jeremy said,

    on May 12th, 2011 at 2:15 am

    i’ve not tried to load it to that kind of cartridge before. I always used the nintendo flash carts or the now impossible to find lik sang variety. USB was pretty exotic back then. I don’t have any gb dev hardware any more, maybe the guys at can help?

  3. Filip said,

    on July 30th, 2011 at 11:43 am

    The emulator I’m using displays the block list incorrectly ( screenshot ). I want to know if this displays correctly on a real gameboy colour, so I can file a bug with the emulator.

  4. Filip said,

    on July 30th, 2011 at 12:21 pm

    I have changed the background colour, and now it displays correctly. This seems to only happen if Fatass formats the SRAM when it’s started up.

  5. Filip said,

    on July 30th, 2011 at 12:23 pm

    Changing the background colour doesn’t seem to fix it after all.

  6. theArtist! said,

    on September 3rd, 2011 at 9:15 pm

    @baseck: probably due to bad header data (rom size) – use rgbfix or any other header tool to fix it and try again.

  7. Derrick said,

    on February 2nd, 2012 at 8:39 pm


  8. on April 21st, 2012 at 12:11 pm

    [...] Check it! [...]

  9. Chris Gregory said,

    on April 26th, 2012 at 4:04 am

    No luck on a Mac with the KiGB emulator. I’ll try it on something else…

  10. mathias said,

    on April 22nd, 2014 at 6:30 pm

    just checking it out, really cool – is there a way to set pattern length?

  11. Daggdroppen said,

    on February 22nd, 2018 at 1:39 pm

    Hello Jeremy!

    I have been using your tracker for a long time! It is my favorite tracker :)

    Are you thinking about updating it any day?

    Best regards

    / Mattias

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