With FLOS v586+ cards can be MMC, SD or SDHC type. Capacity sizes of 64MB to 4GB have been tested. Some cheap brands are known not to work (on the V6Z80P and other hobbyist projects - lack of SPI protocol support is suspected). Known working brand include:

Kingston
SanDisk
Viking

Please ensure the card is formatted to FAT16 spec - Note: Windows may not allow this (insisting on FAT32 for large cards). If you experience any problems (EG: A freeze when using the FLOS DIR command) please format the card in the V6Z80P using the FLOS command:

FORMAT SD_CARD LABEL

This will truncate capacity to 2GB. To use more space, use the FLOS util Disktool.exe to create and format partitions. Note: Windows XP will only see the first partition, but Linux can see them all.