http://en.wikipedia.org/wiki/Secure_Digital#SDHC It's just a better type of sd card. Does it say "HC" anywhere on the sd card?
High Capacity cards can only be used by better hardware. I think the newer cards like the Acekard 2i can use them
As long as it say SDHC support on the package then it can use SDHC microSD chips. R4 original 2GB microSD chip are a rare "non SDHC" 4GB MicroSD chip
R4 Original only supports 1Gb and 2Gb SD Micro. There was someone who said that there is a 4Gb non-SDHC version in the market but very rare. I never came across such Micro SD when I go shopping for electronics. There is no way the R4 Original can run SDHC Micro SD. Even creating a partition will not make it work.
As has been stated, there are still 4GB non-SDHC cards out there. They are so expensive when you find them though (all because they are uncommon, not really sought after), you would be better off just buying two cheap 2GB MicroSD cards.
