Actually, there are 4GB cards that are SD, not SDHC. I've still never seen a definite answer on whether such a card would work.
SD cards bigger than 2GB = SDHC, which isn't supported by Gecko.
If you use riivolution, you can either get a SDHC card, USB flash drive/hard drive or load hacks via network with a RiiFS server (which I currently do
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Wait hold on, Lemme Get this straight, Yesterday i went to my local wal-mart, and i looked at the SD card section, and the 4GB sd cards were all SDHC. Since i wasn't sure, i didn't buy any, but do SDHC cards work with riivolution? Because i'm not so sure of buying an 4GB SDHC...