This thing reliably locks right onto both stationary and moving subjects, even in reasonably dim lighting.Those who had reported D2x focus issues now also seem to be pleased with things.When done, the display will change to "Update completed.
I had been unaware of these issues previous to the release of the new firmware, but have read reports on the web from users who say their flash problems were indeed fixed with this update.
Some users have also reported a decrease in noise at high ISO settings.
Do not turn it off and don't do anything else with it either.
This should take no more than a couple of minutes (Nikon claims two to five minutes but mine was at the low end).
Nikon USA has the Windows version here and the Mac OS version here. In either case, uncompressing the contents will yield a "D2X Update" folder containing the two actual firmware files, AD2X0101and BD2X0101.bin, along with a release notes text file.