this is just a c/p from different websites these are statment made in the forum

The new firmware version 1.2009.44.1 has solved the problem with ringing tone only going through the connected headset (wire or Bluetooth). Now one also hears the ringing tone in the loudspeakers on the phone itself, when a call comes in.

The Bluetooth stack has also been updated. My N900 is now able to automatically reconnect to my Nokia BH-900 Bluetooth headset after having been out of range for several minutes.