I am following install procedure from: https://github.com/offensive-security/nethunter-LRT
I have tried with stockImage 6.0.1 (MMB29O) and 5.1.1 (LMY47V), NetHunter 3.0 Marshmallow and "BETA-SuperSU-v2.66-20160103015024.zip"

I followed the HowTo... First I had to remove "-p" from "twrpFlash.sh" (as seen in forum thread) that was causing zip file not copy to device.
Then each time last install script gives error from that line: "E:Unable to mount '/data'"

./twrpFlash.sh
NETHUNTER LINUX FLASH (TWRP, SuperSU and Kali Nethunter)

CHECKING PRE-REQUISITES

Checking if adb is installed
adb FOUND
Checking if adb is installed DONE

Checking if fastboot is installed
fastboot FOUND
Checking if fastboot is installed DONE

Adb connection check
ADB device detected.
Adb connection check DONE

Checking TWRP image existence
Dir twrpImage/ has files
Checking TWRP image existence DONE

Checking SuperSu existence
Dir superSu/ has files
Checking SuperSu existence DONE

Checking Kali Nethunter zip existence
Dir kaliNethunter/ has files
Checking Kali Nethunter zip existence DONE

CHECKING PRE-REQUISITES DONE

Sending Kali Nethunter zip to the device
4648 KB/s (687443356 bytes in 144.414s)
Sending Kali Nethunter zip to the device DONE

Sending SuperSu zip to the device
4298 KB/s (4272471 bytes in 0.970s)
Sending SuperSu zip to the device DONE

Rebooting into bootloader
Rebooting into bootloader DONE

Flashing TWRP image
sending 'recovery' (8956 KB)...
OKAY [ 0.287s]
writing 'recovery'...
OKAY [ 0.318s]
finished. total time: 0.605s
Flashing TWRP image DONE

Booting into TWRP (20 secs dont worry)
downloading 'boot.img'...
OKAY [ 0.286s]
booting...
OKAY [ 0.029s]
finished. total time: 0.315s
Booting into TWRP DONE

Installing SuperSU
TWRP does not appear to be running. Waiting for TWRP to start . . .
Press CTRL + C to quit.
E:Unable to mount '/data'
Unable to locate zip file '/sdcard/supersu.zip'.
Installing '/sdcard/supersu.zip'...
Checking for MD5 file...
Skipping MD5 check: no MD5 file found
E:Failed to sysMapFile '/sdcard/supersu.zip'
E:Error installing zip file '/sdcard/supersu.zip'
Done processing script file
Installing SuperSU DONE!

Installing Kali Linux Nethunter
E:Unable to mount '/data'
Unable to locate zip file '/sdcard/kaliNethunter.zip'.
Installing '/sdcard/kaliNethunter.zip'...
Checking for MD5 file...
Skipping MD5 check: no MD5 file found
E:Failed to sysMapFile '/sdcard/kaliNethunter.zip'
E:Error installing zip file '/sdcard/kaliNethunter.zip'
Done processing script file
Installing Kali Linux Nethunter DONE!
Rebooting into Kali Linux Nethunter
Everything is installed. Phone should be booting up! Enjoy
I cannot understand what is wrong?
Is there something else to do?

Thanks