The phone officially supports up to 32GB (SDHC). This doesn't necessarily mean you can't use a 64GB (SDXC) card, but you are taking a little risk. Unfortunately, a quick search doesn't find any inf on this phone/sd combination so the risk may be yours. I put a 64GB card in my wife's E4GT (Samsung Galaxy S2 variant) which also supports up to 32GB. It didn't initially recognize the card, but after a reboot it worked like a charm. This doesn't mean you absolutely will have success. The best advice if you decide to try this is to avoid the off brand cards. Stick to the higher quality name brands (Sandisk, Patriot, Kingston, ect.) to increase your chances of success. Good luck!