I've been wanting to make a PSF2 playlist of Legaia 2 Dual Saga. There's a few extra tracks not in the OST as well as some altered ones. I followed the instructions on the PSF2Kit's CSL how-to, but I've only made some progress. The CD contents consist of .PAC files, an .IMG file, .BIN files, a .DIR file, and the standard SYSTEM.CNF and SLUS_XXX.XX files. I figured out the format of the .PAC files in that they're just some byte padding at the start, followed by the file size, some more padding, and then a set of file pointers and their pathnames, followed finally by the files themselves one after another. I was able to extract LIBSD.IRX easily, as the instructions call for. However, it calls for other files not present in any of the .PAC files, which would be a few more .IRX files, and DEFAULT.** named files which are identified by tags starting with 'IECS'. The .DIR file is unknown data from start to finish, although I have a feeling it's composed of a bunch of MD5 hashes. The .BIN files aren't recognised as disc images of any sort, but interestingly, all three .BIN files seem to end with chunks of human readable MIPS assembly code, including calls to functions I've identified in a homebrew PS2 dev kit through Google search. I've not touched the .IMG file aside from attempting to open it as an archive.
