A similar questiosn was asked here

But mine is slightly different.

I am stuck on step 4 in the OP question in the above link. I am using cooja motes (add border router first then hello-world mote)

~/contiki-ng/examples/rpl-border-router$ make TARGET=zoul connect-router-cooja
../../arch/cpu/arm/cortex-m/Makefile.cortex-m:6: ../../arch/cpu/arm/CMSIS/CMSIS does not exist or is empty.
../../arch/cpu/arm/cortex-m/Makefile.cortex-m:7: Did you run 'git submodule update --init' ?
../../arch/cpu/arm/cortex-m/Makefile.cortex-m:8: *** "".  Stop.

So I do git submodule update --init :

~/contiki-ng/examples/rpl-border-router$ git submodule update --init
Submodule 'arch/cpu/arm/CMSIS' (.git) registered for path '../../arch/cpu/arm/CMSIS'
...
Submodule path '../../tools/sensniff': checked out '70029fc5b21485cfd4afb8037c49661212d0935a'

Then I try make again, but now I get this error:

:~/contiki-ng/examples/rpl-border-router$ make TARGET=zoul connect-router-cooja
../../Makefile.include:157: *** Target "zoul" compiler "arm-none-eabi-gcc" cannot be found.  Stop.
~/contiki-ng/examples/rpl-border-router$ l
Makefile  README.md  border-router.c  build/  project-conf.h  webserver/

this is my ls /dev/tty* output :

~/contiki-ng/examples/rpl-border-router$ ls /dev/tty*
/dev/tty    /dev/tty12  /dev/tty17  /dev/tty21  /dev/tty26  /dev/tty30  /dev/tty35  /dev/tty4   /dev/tty44  /dev/tty49  /dev/tty53  /dev/tty58  /dev/tty62  /dev/ttyS0
/dev/tty0   /dev/tty13  /dev/tty18  /dev/tty22  /dev/tty27  /dev/tty31  /dev/tty36  /dev/tty40  /dev/tty45  /dev/tty5   /dev/tty54  /dev/tty59  /dev/tty63  /dev/ttyS1
/dev/tty1   /dev/tty14  /dev/tty19  /dev/tty23  /dev/tty28  /dev/tty32  /dev/tty37  /dev/tty41  /dev/tty46  /dev/tty50  /dev/tty55  /dev/tty6   /dev/tty7   /dev/ttyS2
/dev/tty10  /dev/tty15  /dev/tty2   /dev/tty24  /dev/tty29  /dev/tty33  /dev/tty38  /dev/tty42  /dev/tty47  /dev/tty51  /dev/tty56  /dev/tty60  /dev/tty8   /dev/ttyS3
/dev/tty11  /dev/tty16  /dev/tty20  /dev/tty25  /dev/tty3   /dev/tty34  /dev/tty39  /dev/tty43  /dev/tty48  /dev/tty52  /dev/tty57  /dev/tty61  /dev/tty9

related questions that I am looking into, to aid me in finding a solution: RPL Border Router running in Contiki Cooja IoT device networks and border router in Cooja How to access DIO message of RPL on Contiki Cooja simulator? is it possible to call a web service from cooja?