I think I posted this back in November - maybe not to this site though.  Anyhow, just doing a reinstall on a laptop and was reminded of the P2 Format Station release form Panasonic. 

This free little App from Panasonic allows you to format 16gb and 32gb cards with your laptop and maintain readability in camera. For those of you who don’t know, since the 16gb firmware update, you were unable to format those cards with a laptop. Upon reinserting the card into the camera you would get a read error.