Officially SD/MMC cards up to 256MB on FAT16/32 are supported. I have a SanDisk 2GB and 512MB (both FAT16) in use with no issues at all. I also have seen several people using 1GB SanDisk an no-name SD cards. There is a virtual file/folder limit of 400 which I haven't touched (I have 377 files taking about 1.7GB on my 2GB SD card) and which may prevent you from fully utilizing a 2GB or bigger SD card.