Nokia BH-609 hard reset
To repair and reset your Nokia BH-609 :
Clear settings or reset Nokia bh609 Bluetooth headset
To clear all the settings from the headset (including settings you have defined with the Nokia Accessory Setup Application), switch off the headset, and press and hold the multifunction key for about 8 seconds. The headset beeps twice, and the red and green indicator lights alternate. After the settings are cleared, the headset enters pairing mode.
To reset the headset if it stops functioning, even though it is charged, connect the headset to a charger while you press and hold the multifunction key.