Furious Advance Tracker (or FAT for short) is a tracker written by Cyril Brouillard (AKA spintronic). It's a limited stripped down LSDJ clone for the GBA. It features the standard 4 channels of the Gameboy, those were only supported in versions 0.1.0 and 0.2.0. In those versions the 2 sample channels were just dummy channels. The latest version of FAT,version 0.3.0, has functional support for the 2 sample channels, however it is still in a bit of a buggy state and the tempo is kinda sloppy, therefore this version is for experimental purposes at the moment.
For now, FAT 0.2.0 is recommended, even though you won't get the sample channels, you will still be able to save songs and have the ability to reach higher tempo speeds. Please note that only 3 songs can be saved, and version 0.1.0 has no saving at all.
The source code can be found at GitHub here
The latest version of FAT was uploaded 5 years ago, therefore FAT development has been pretty much discontinued for the last 4 years. However, the bright side is that he left the source code available for anyone to make a fork of the tracker and fix all the known bugs that are present in the 0.3.0 release.
Recently, as of 08/03/15, Cyril Brouillard has modified the GitHub for this tracker.
Currently, it is unknown that their will be a new ROM image of FAT available for download any time soon. However the tools that he used to billed and compile FAT are available for anyone to compile the ROM themselves.
Update, 08/11/15, Furious Advance Tracker has got a new website! you can check it out here
a new ROM is also available for download.