I am new to Android so if asked a dumb question please bear with me. For those phones on old Android versions like 1.5, 1.6, 2.1 etc, when 2.2 come out, can they be upgraded to 2.2? If so do they need the original manufacturer to rollout a new firmware to upgrade? Or they can be upgraded from Google? How about HTC Desire, Legend? Can they be upgraded to 2.2? Thanks.