I got a replacement iPhone 4 last weekend, due to a home button that had died. However, it seems that the replacement has an issue all of its own - the earpiece. Whenever someone's talking, it buzzes, as if there's a piece of debris inside the earpiece. It's far more noticeable when talking to someone with a deep voice. The phone it replaced, definitely didn't do it. Planning on taking it back to the Apple store that gave it to me. Is this a known issue? Is there some kind of secret handshake, whereby I can fix this myself easily? To be clear, I'm not talking about dismantling it!