But... Doesn't every MicroSDXC card support up to the maximum available addressing limit? If it supports a 64GB card, it should also support a 512GB card, thoug

But... Doesn't every MicroSDXC card support up to the maximum available addressing limit? If it supports a 64GB card, it should also support a 512GB card, though the manufacturer probably doesn't want to guarantee anything that doesn't exist yet.