I’ve updated my Nikon D3’s firmware successfully, downloading it from Nikon USA. I’ll report on any glitches that I might encounter.
But the main glitch is that Nikon US has inexplicably chose a confusing approach in distributing the update, choosing StuffIt (SIT) format instead of the perfectly fine (and built-in) ZIP or DMG format that Mac OS X has supported for years now (Windows users are treated to an EXE, thus opening a new vector for viruses to spread). On my system, the SIT file yielded a “can’t unstuff” error message that prompted me to go to the Stuffit site, register to get a newer version, etc. What a hassle. It turns out that the error message was erroneous, and I was able to “unstuff” without downloading a new StuffIt Expander.
Bottom line: the KISS principle applies here (Keep It Simple, Stupid). A ZIP file which expands to the two binary files will do just fine.