New firmware released from SONY Japan.

Hard to tell because I don't know about the update you installed. I haven't seen any detailed information about this one either and all I know is this is version 1.01, released 2013/02/05, and that it mainly provides PDAF support for SEL50 and some other lenses. It might or might not include bugfixes/minor improvements on the side (they're not always announced).

What was in that firmware update from last December? I don't remember previously installing any updates for NEX-6 except the lens firmwares last year. If there has been an update for the camera body I've missed it.