I know that if there is a 4GB SD card that works flawlessly, I'd like to use it. There are a bunch of new SDHC cards that the new firmware for the R-09 now supports, and while there are 4GB SDHC cards that are approved and will work great, they will not work with our current SD card readers. SDCH cards are not backward compatible. I wouldn't be able to use any SDHC card in my other devices.