Browsing romhacking.net today ( http://www.romhacking.net/forum/index.php/topic,12243.0.html ) I came across ROMulan Data Extractor/Injector and thought it would do well here. Homepage (downloads and example formats for a few megadrive games) http://stealth.hapisan.com/ROMulan/ Documentation http://stealth.hapisan.com/ROMulan/ROMulan.html Do pay attention to the license http://stealth.hapisan.com/ROMulan/ROMulan.html#License (it should not trouble most rom hackers and projects but it is not a standard license and has some special conditions) Some waffle from me Quite often we get questions when people figure out file formats or have minor variations on existing formats where adjusting several hundred (or more) entries by hand is not ideal. Traditionally the reply is find a capable programming language and build your own tool which is not that nice for something simple enough to understand but large enough to render manual work tricky (it helps and there is a lot of overlap but you do not necessarily need to be a programmer or indeed a programmer of tools to be a rom hacker). This goes double for the newer consoles where they have formats stacked on top/inside of other formats. Granted there are tools like Altas and romjuice that are mainly aimed at scripts and pointers where this is more of a general archive unpacker. Better yet it is command line (granted it has a script aka "injector" to do various things) so you can chain it easily enough. Naturally for a tool of this calibre it is something of a programming language unto itself but it is geared towards the sort of things you want to do as a hacker rather than the scope of activities a full on programming language might encompass. It is still good to at least have some simple scripting languages along the lines of python or perl .or maybe some C# but this should help bridge things. Depending on how this plays out I might see about making a script collection for known DS and other console formats (SDAT, ARC, NARC, NANR and the like) as such things are a long time coming. I might also see about finally making a relinker for the DS. If you want a head start on trying such things I would suggest a simple script at first (the BMG format Animal crossing and NSMB use is ideal) but http://nocash.emubase.de/gbatek.htm#dscart...roromfilesystem is the DS file system. http://llref.emutalk.net/nds_formats.htm http://llref.emutalk.net/docs/ http://www.pipian.com/ierukana/hacking/ds_narc.html http://www.pipian.com/ierukana/hacking/ds_nff.html http://treeki.shacknet.nu/romhacking/docs.html http://kiwi.ds.googlepages.com/sdat.html http://kiwi.ds.googlepages.com/nsbmd.html http://www.amnoid.de/gc/ (for the gamecube and something sort of for the wii) http://hitmen.c02.at/files/yagcd/yagcd/frames.html (sections 14 onwards) There are countless other places and threads that detail formats and example hacks as well. http://gbatemp.net/index.php?showtopic=122534 Much of the old demo/hidden/beta tracks from mario kart used similar techniques. If you look at the recent http://gbatemp.net/t276441-inazuma-eleven-e-full-project it has a nice example of the need for such a program.