Restoring Your Subwoofer to Factory Settings | Bose Lifestyle Ultra Subwoofer
To restore your subwoofer to factory settings:
Press and hold the RESET button located on the rear of the subwoofer for 10 seconds, until the status light blinks white twice.
The reset is complete when the status light pulses various colors.
If your subwoofer was wirelessly connected to your soundbar, see Setting Up Your Subwoofer to reconnect it.