I've just installed ubuntu on my PS3, and managed to set up the wifi and 1080p res with a bit of work in the terminal window. However when i go to shut down, ubuntu doesn't shut down fully, there's a black screen with a single flashing cursor and it just hangs, i have to physically switch off the power button at the back of my ps3. Any suggestions to fix this?

Also when I'm logged in to linux, it spits out cd's and dvd's after a few seconds of playing. HELP