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I assume that there would be the official Nokia memory cards that work with, namely the MU-xx line. However, as there have been users that have had microSD cards not working from brands from anywhere to Lexar to SanDisk, I thoroughly suggest that if possible, buy a cheap microSD card first and test it in-store with a 820 demo unit. Just to be double sure. Apparently there's a fix for the memory card issues, but for now that is the best you can do unfortunately.