Done it before on my GH3 - just can't remember how to update the firmware. Cannot find it in the manual or in the camera menu - HOW?
Found it - PLAY buttom :)

Here is the link.
Joint update service for Four Thirds body and lenses | Download | Digital Camera | Digital AV | Consumer Products | Support | Panasonic Global (http://panasonic.jp/support/global/cs/dsc/download/fts/index.html)

My camera would not update. I contacted Panasonic Tech Support they are in the process of sending me the update on a SD card. That process takes 10+ business days. Waiting.

Kent