Just a quick note for anybody doing this upgrade. It seems to me that it would be very easy to end up thinking it was done before it was really done, and hence pushing the buttons when you weren’t supposed to, and they say this might end up bricking your camera. So be careful out there!
(Instructions and firmware download here.)
The problem is, it goes through several states that look like normal terminal states along the way, before it reaches the real end. I saw the screen blank for a while, and I saw some normal displays. It really does take the 1-2 minutes they say, it’s not done much quicker. AND that little tiny green LED in the middle of the back stays on, at least through the blank screen.
I would strongly recommend reading the instructions very carefully, checking your watch when you start the upgrade, and being very patient!