fuzzy earpieces are normally a hardware issue, not a software one. WHat you should do is reflash it with generic firmware and if this doesnt fix it then take it back to where you got it. Dont tell them its been flashed and debranded. Claim it was like that when you got it ONLY if they ask. I have sent a flashed and debranded o2 phone back under the o2 warranty and noone even batted an eyelid! Denial is a great defence!