After iPhone OS4 update, Bluetooth may act weird. I fixed it by doing this.

After updating my 3GS I noticed that Bluetooth audio didn't sound that
great, there was obviously some breakage up as if some of the audio
stream were getting dropped or clipped. I have a BlueAnt Q1.

Removing and re-pairing the headset resolved it but only when I did a
reset after removing the device.

The steps:

1. In Settings, General, Bluetooth select the device and then select
'Forget this device'.

2. Reset the iPhone (hold the home and top buttons, etc).

3. Pair the headset with the phone again.

All was working fine again.

Posted via email from ken5m1th