My wife has a horrible habit of allowing the battery in her iPhone 4 fully discharge. Just recently (in the last week or so) she has noticed that after charging the phone again the external speaker doesn’t work properly. Pre-installed tones work, but game sounds and music don’t. Also the volume slider doesn’t show when music is playing and volume keys wont work.
We have tried soft resets, erasing settings, changing settings and basically everything I can think of short of a full factory reset. The problem resolves it’s self after a few hours, but is annoying nonetheless. While the speaker isn’t working she can listen to music and other sounds by plugging headphones in.