Just received my 100u and popped in new cards-won't work with class 10. Surprising that the camera doesn't have the updated firmware halfway through 2011. So I went to the JVC Pro site to download it and I get "unable to find details of specified mode. Please go back to Firmware Upgrade page."
So does anyone have the firmware they can make available to me?

It's possible there could be other issues preventing you from updating the firmware, or even that there's a problem with card you're trying to use. First try some other cards if you can. Seeing as your cam is new I would work with JVC support to resolve your issue in case there's a problem with the cam itself not reporting the correct information to the updater, or something like that. Put the onus on them to see your issue through rather than doing something that my invalidate your warrantee. I realize working JVC support may be the more time consuming option but then at least you're covered. I forgot to mention, just use class 6 cards if you have work that must be done right away, or until JVC resolves the problem.

Thanks for the heads up. JVC support came through and sent me the firmware. Camera now supports class 10.