I noticed the orange icon in the status bar and started the PR1.3 update. After various prompts and downloads, my N900 now constantly reboots (approx every 10 seconds), having the normal start-up screen (blue Nokia logo on white background) and "Installing of software update. Please do not interrupt" in the bottom of the screen.

Has anyone else the same problem?

Worst come worst, you can always just reflash your N900 to PR 1.2 .. I've done this many times (once to overcome the reboot issue) ..

http://wiki.maemo.org/Updating_the_tablet_firmware

I personally haven't switched to PR 1.3 through ..

Thanks, it is fixed now and PR1.3 installed! (Luckily I was able to find WinXP machine as Win7 does not seem to be supported)