I feel like I have to be missing something obvious. When I check for software updates, it tells me my current version is 777, which is true. It says the available updates are 777...no update required. I'm doing this the same way I've done previous updates, so I'm at a loss at how to download the 784 revision. Am I doing something dumb? (now there's an opening for you)
Edit: I'm guessing it is no longer available for download. If that's the case and it was removed as the latest available build, I'd be leery of flying with it if I had already updated to 784.