I have tried using the Sandisk 4gb SDHC card in my M8 (1.06 firmware) and the two do not play well together. If you try to format the card in the M8, the card writing light will blink forever -- only removing the battery will restore the camera to functional status. When the card is formatted on a PC and then placed in the camera, the camera reports it as "full" even when it contains no files. Obviously, the camera (at least with 1.06) is not SDHC compliant (or the Sandisk card doesn't meet the standard). In either case, they don't yet work together. I'm confident this will be fixed, but at this time I would advise against buying any 4gb card that isn't specifically on the Leica list.