2011 WRX Premium Sound
iPhone 4 w/ OS 5.01
I see "UNSUPPORTED" on the screen everytime it doesn't work. Everything was working fine for months with iOS5.0 beta and iOS 5.0 GM until two days ago when I got "UNSUPPORTED" on the screen of the in dash receiver.
-Updating to 5.01 didn't help.
-Rebooting the phone didn't help
-Force Quitting the Music app didn't help
What did temporarily help though disconnecting the battery lead from the car for 5 minutes then reconnecting it today (while using iOS 5.01) did allow music to playback to work the next time the iPhone was connected but only for that one time, now I'm getting "UNSUPPORTED" again.
To me this seems like a software bug and specifically a state machine issue, though it's unclear if it's caused by the iOS or the head unit, but it must be that something in iOS has changed that it replies with "UNSUPPORTED" rather than just working like it used to. This is either a bug in iOS or a change that was made in iOS that it now doesn't work around issues that it used to.
Note: I've also noticed that my home alarm clock radio can no longer charge my iPhone though I can still play music through it, so clearly apple has made changes to some dock related detection / charger detection functionality.