I kept it plugged in as I'd had a 'died in its sleep' situation just before the update, which started a cycle of resetting as I went on to unroot, restart, then installed the update, restarted twice... and then rerooted and restarted. It took a few seconds before showing the battery status, and I've noticed the WiFi status bar icon doesn't like to show the current status of the WiFi.
Time to test it out, and see if it'll die in its sleep again.
