Well, now I'm in trouble. I downloaded, extracted, and moved the file to the root of my card. I got the android guy, and it rebooted to the splash screen saying 20110116 in the corner. It flickered, and the same splashscreen came up again, as usual. But it froze there. It does not move on or change in any way. I can no longer turn the device off except for as long as I hold the reset button in. So I tried rolling it back to yesterday's version by deleting today's file from the card (and noticed there is no longer a LOST dir) and putting yesterday's file on. Now I have 20110115 in the corner, but it's still frozen, as in the splash screen doesn't change, and I can't power off. So I tried the last PB version. It's still frozen on yesterday's splash screen. FWIW, when I plug it into my PC, everything looks normal. I guess I'll have to wait for the battery to discharge to get it to shut off.
Any ideas what I can try? The only way I know how to do a factory reset is from Privacy, and since I can't get to it, that won't work. The reset button on the top only works for as long as I hold it in, and then it boots to the splash screen and stops.