The best you're likely to get is 32GB. The most likely you're liable to get is "no card installed" or "defective card", or messages to that effect. It's not like desktop RAM, where there's an address line flapping in the breeze if the RAM is more than the motherboard can support. There's a little computer in those cards, and a 64GB card is telling a phone that can only use 32GB on a card things it doesn't understand.