Have been running iOS5 fine on my iPhone and have even reverted at one point which solved all the issues. 1. At around 20% battery if I attempt to unlock the phone or even if it is running an app the screen will simply go black, there's no obvious shut down process. I can then boot up again and it reports the same ~20% battery and runs fine for the remainder. This has happened 3 times now. 2. After a reboot the unlock slider is unresponsive. I have to mess around turning the screen off and then using the camera slider to get in. Has anyone else experienced these issues? I'm thinking of reverting to 5.1.1 as it's unlikely they will bother fixing them if they're 3GS specific. Don't want to lose the iMessage link with iPad and OSX though, and can't work out if I would?