I ordered this one from Amazon and it does NOT work with the GH3:
http://www.amazon.com/gp/product/B0080KN18K/ref=oh_details_o00_s00_i00?ie=UTF8&psc=1
I have a much larger HDMI converter working so I can isolate this new converter as the problem. Also when powered either by the usb power or by HDMI directly a blue light inside turns on, and I see a vertical color pattern on my monitor, so I know the HDMI converter is powering on. I tried all HDMI output modes including auto on the GH3, and multiple HDMI cables, and nothing worked.
I also ordered the Freefly version and was disappointed to see that it came with a medium thickness mini HDMI to mini HDMI cable. The Hyperthin cable is way thinner and more flexible, much better for brushless gimbals, but it only comes in HDMI -> HDMI mini, which would be perfect if the Freefly used a regular HDMI input like every other converter. But since it uses mini input I'll need to use another regular to mini converter making the Freefly converter almost as big and bulky as my $20 ebay converter.