New Super Mario Bros shouldn't need any fixes with the newer versions of the USB loaders (I use USB LoaderGX myself out of preference but they all work much the same anyway)
Older Loaders needed the 002 fix enabled so you can try that
Other things older loaders needed was cIOS 38 rev 14 or higher and to use an alt dol with some loaders as well if the loader supports alt dol loading
P.S. 16GB isn't a lot of space some games are around the 8GB size even when in wbfs format, you will want at least a 300GB HDD to get a decent collection of Wii, homebrew software and roms on there, 16GB will store apx one of the bigger games and few small games and a lot of time to remove and replace games as and when
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