How to diabale BT and use TX2's ttyTHS3 as an common UART ?

I have read the migration between TX1 and TX2, It’s said :

“In addition to bringing UART[2:0] out on the module pins, Jetson TX2 also provides an
option to bring out UART3. This is multiplexed with the on-module WLAN/BT, so if this
is being used, UART3 will not be available. A 2-pin UART (UART7) is also available on
RSVD Pin D8 and Pin D5 on Jetson TX2.”

but how can I use UART3,and disable the BT ?

THANKS~~~~

Please refer to this topic
https://devtalk.nvidia.com/default/topic/1021563/?comment=5199388