Just to amuse you all a little really,
I have a 4s, been going strong for 4 years! No marks etc, perfect condition.
Anyway, out walking back from lunch, using headphones whilst on the phone to someone. - Battery dies.
Get back to work and charge it, turn it on, go to make another phone call, this time I can't hear them, thought, oh must be there issue.
Called someone else, same thing happened again. Okay good old IT trick, turn it off and on again. Still the same thing happened, I wasn't getting any sound out my speaker.
When I adjusted the volume, I noticed it was still in 'Headphone' Mode - So made another call, this time on loudspeaker, could hear them fine.
Plugged in headphones, could hear sound again etc. Took them out, still in stupid headphone mode.
I then went into sound options, when I select a ring tone, works fine but still in sodding headphone mode, and there is no option to turn it off and on.
So basically my phone is always thinking my headphones are plugged in.
Chances are my Jailbreak has bugged it, but I can't be bothered to restore!
Anyway, hopefully that will brighten up your wednesdays afternoon.