In case it matters: I tried to do the OTA update (no CSSU, KP47) using HAM and got an error that my battery was low (17%, should be plenty..)

So I plugged it and did the update. After a while the screen went blank (gray, not black like when you lock it) and nothing happened. I thought maybe it takes longer or something, but after another while I decided to turn it off and then on again (with the associated nervousness as I thought I might have to reflash my N900 for the first time .

Everything works as before (the update is installed according to Settings - About as well as apt-get upgrade).