Here are the steps to change the BT baud rate

1. Connect the jumper to change the BT charger into programming mode
2. Plug in the power
3. unplug the jumper to then plug in the jumper again to set the baud rate
4a. If the LED flash once, the baud rate is 4800
4b. If the LED flash twice, the baud rate is 9600
5. When the desired baud rate is set, unplug the power
6. unplug the jumper to finalize the setting.