Softmod Only, Disc Loading = YES IT DOES WORK!!!!
I have a 3.2 Japan system, running New Mario Bros through DVD thanks to the code in the thread "Crack for New Mario Bros" (or something like that) on this board. Some dude was very nice and made a GCT file for download in that thread, I just used that combined with Gecko with the option SD Card code Yes and now it works perfectly, I played all the way to world 2 without any freezing or errors. The key is, you need to use this code on the UNFIXED version of the game that was available on the net the first day, NOT the Fixed version. If you use it on the Fixed version it doesn't work for some reason. I keep getting green screens with every loader i tried (Neogamma, Gecko, Backup Loader, Softship, etc). The Unfixed version, however, works wonderfully.