Hi, I had once this problem. I disassembled the speaker enclosure and put some electronical cleaner (spray) in the speaker... After letting it dry, I reassembled the phone and all worked fine again.... Hope this will help you
It is me again. It worked! It's incredable. I hit with my Hand against the backside of my iPhone and it vibrates now. I Never beliefed it, that you have to Hit a device valued over 600€... LOL In other words... You have to hit if you want something. I LOVL
I am new here and I have the Problem too. On a French forum I saw a strange thing but for several people it worked. With the hand, give a tap on the backside of your iPhone 4. I'm Not sure if it works as mine is covered and I will bring it back...