O2 xda Loudspeaker problem

I have been suffering from the same problem.... am not exactly sure as to what is happening but after what i observed it tends to happen when u plug in or plug out the USB handsfree that comes with it. I tried several things including what you people already mentioned. But there is 1 solution that worked with me. I had reinstalled the O2 firmware on my phone again which was obtained from the O2 website itself and it started working fine again. So try it for yourself. Dont forget to backup your data and remove your memory card before reinstalling the firmware.