WHAT:

Ok first things first. This is NOT the best way to resolve this but it did work for me. No guarantees with this. Proceed at your own risk!

This was done on a Kali 2.0 Sana machine attempting to install Nethunter 3.0 to a Stock OnePlus One with Android 5.1.1.

Before you begin you will need to download the nethunter image for your phone, TWRP form the TWRP website for your phone, and the OnePlus One stock image. Also you will need to know how to use ADB to boot into fastboot and push files to the phone.


So the issue I had was that after the nethunter installer failed I had to start manually installing nethunter on a OnePlus One.

I found that attempting to flash TWRP manually (fastboot flash recovery twrp-2.8.7.0-bacon.img) was failing despite fastboot telling me it was a success. It would still bring up the stock Cyanogen as the recovery.


FIX:

In order to fix this these were the steps I had to go through.

First boot into fastboot per the instructions at TWRP.

Then run:
Code:
fastboot flash boot twrp-2.8.7.0-bacon.img'
###### I know this is the wrong partition to be flashing too! Just hang in there with me for a second. Also you may have a differenct TWRP version. #######




Then reboot the phone. #### FYI your phone will forever boot to TWRP recovery at this stage. We will fix this in a second. #####


Once in TWRP recovery you will need to select INSTALL and select the NetHunter .zip file. If you dont have it saved to the phone yet you can push it to the phone with adb.
Code:
adb push <nethunter.zip> /sdcard/

Once the NetHunter install is finished you will reboot and notice TWRP will come back up. ### I know... Again we WILL fix this ###



Take the Cyanogen OS image you downloaded earlier (the OnePlus stock image) and extract it. Change into the directory where boot.img is located, inside the extracted Cyanogen OS image directory.


So again boot back into fastboot using ADB.


Once your phone is back in fastboot you will run:
Code:
fastboot flash boot boot.img
###### This will fix the boot issue and you will now see NetHunter boot up on reboot ######


Then run:
Code:
fastboot continue

You should now see the sweet welcoming image that is the Kali NetHunter boot up sequence.


Let me know if someone has a better way. This was just the way I did it and though I would share.