rpl-border-router can't use tsch ?

[tlzfighting]

Hi , sir ! I want to ask you some questions about tsch .
My rpl-border-route mote which uses tsch can not work right.
How can I solve this problem? Looking forward to your reply!
I added the following to Makefile:
MAKE_MAC = MAKE_MAC_TSCH

contiki-ng-develop/examples/rpl-border-router-1$ sudo make TARGET=cc2538dk connect-router

sudo ../../tools/serial-io/tunslip6 fd00::1/64
********SLIP started on /dev/ttyUSB0'' opened tun device /dev/tun0''
ifconfig tun0 inet hostname mtu 1500 up
ifconfig tun0 add fd00::1/64
ifconfig tun0 add fe80::0:0:0:1/64
ifconfig tun0

tun0: flags=4305<UP,POINTOPOINT,RUNNING,NOARP,MULTICAST> mtu 1500
inet 127.0.1.1 netmask 255.255.255.255 destination 127.0.1.1
inet6 fe80::b4b9:8473:81c5:2802 prefixlen 64 scopeid 0x20
inet6 fd00::1 prefixlen 64 scopeid 0x0
inet6 fe80::1 prefixlen 64 scopeid 0x20
unspec 00-00-00-00-00-00-00-00-00-00-00-00-00-00-00-00 txqueuelen 500 (UNSPEC)
RX packets 0 bytes 0 (0.0 B)
RX errors 0 dropped 0 overruns 0 frame 0
TX packets 0 bytes 0 (0.0 B)
TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0