Yes, you can use the 2GB cards. They work as is.
There are even threads here on how to use larger cards, but those require some hardware modifications. I went from a 2GB standard card to a 4GB SDHC (which I had to cut up to fit. But the 2 GB cards work fine. There is (was) someone on here selling a premodified 8GB card for the 770.

I've seen the threads on flashing to the memory card, but not sure where they are off hand.

desiv