Gecko OS is not the problem; it's the file patch code that is limited to SD.
This is because:
-A loader/launcher reads the codes from a gct and patches them in the Wii's memory.
-The file patch code uses Brawl's function to read SD cards.
Simply the File Patch Code won't work if launched from an SDHC because SSBB doesn't support SDHC, other codes will work from an SDHC but FPS won't.
*Riivolution works in a completely different way, which makes it compatible with every Wii game and not just Brawl. Also allowing SDHC support and games that don't have SD support in the first place.
I know that, but, for example, can I use a 16GBs SD Card to load hacks with File Patch Code?