1. To reset the speaker

1. Long press the phone call button to shut off the speaker2. Connect the charger3. Long press Volume up button and phone call button together till the indicator light blinks blue and red4. Open your phone and in blue tooth settings, find the head phone and connect

1. To Connect dual devices at the same time

1. Power off the speaker2. Long press the phone call button till the indicator light blinks blue3. Find in the second device the headset and connect4. Open the first phone, find the headphone and reconnect

XiaoMi blue tooth earphone successfully connected to dual devices at the same time, both devices are now transmitting audio via the blue tooth headset.