The Replay has been tested with various sdcard sizes and partitions.
4/8/16/32gig with fat32 formatting.
Note: For anything currently over 32gig you will need to use currently linux to format them as currently windows for example will only support upto 32gig on fat32. (Sandisk is a preferable format). SD & SDHC SDA V1&2 spec.
Preferably class 10 are the current preferred speed.
Currently the Replay has been tested with scards upto 200gig in size.
As we support the SDXC standard, it should allow upto 2TB cards in size.
Also note with 64gig SDXC spec cards, they must be formatted fat32 not exfat using example gparted. You could use virtualbox and ubuntu and cmd line option to do this. See this link for more information.