Check this out:
I followed the NSMG Guide and am playing the game from a 16gb usb flash disk. But for my brothers sake, can I create a NSMB channel so he can launch straight from the wii system menu as apposed to going through USB loade or wii coverfloader?
yes you can!
try using loadstructor (Cluster's Home Page). it was recommended by one of the threads in this site.
the app is very easy to use. you just need to follow the instructions on the site and to get yourself a common-key.bin file (google for it), since it's needed in the app folder.
i was able to build channels for all the games i've tried (including NSMB - PAL version). good luck!
system menu 4.2u (wii NTSC-J changed to NTSC-U) - preloader 0.30 r4 - HBC 1.0.6 - bootmii as IOS
cIOS 38rev14 - cIOS 222/223 - USB Loader GX - NeoGamma r7