I actually have a 2Gb micro in thier right now. It works fine for me up to 1.3GB . I actually filled the card up to 1.8 GIG and it for some reaeson all the folders with the songs were empty. I havnt had much of a chance to play around too much with it. It may have just been acting funny with the buggy software. I will report back when i get a better chance to play with it.
The @ gig sandisk micro sd memory card does work fully functional when you get the firmware update (which you have to get from a sprint store)be sure to call and see if they are capable of doing so I went to 2 that coulddn't.I purchased my card from best buy their price was 119 but I seen it at a kiosk at the mall and they called it and matched the 89 dollar prioe of the mall.