In order to port NetHunter to a new device, it's important to understand how NetHunter is separated. NetHunter is divided by the rootfs (also known as the chroot but will be referred to here as rootfs) and the kernel. For the most part, the rootfs is not important to your Android device as it only contains Kali. The kernel is integral to getting things like Bluetooth, wireless USB, and HID keyboard (etc) working.
You also need a device with an unlocked bootloader, for flashing the kernel, and you must be able to get root on the device. Root is needed so we can write applications to system, such as busybox and bootkali, and execute commands that allow us to get Kali running.
tl;dr: If you are looking to port a device, it's all about the kernel. Device must be unlockable/rootable.
Let's assume that you've already followed the directions on the main GitHub page. You have all the dependencies met and you are ready to go. The first thing we want to do is build a test kernel.
If your device is older, please check to make sure your kernel version is 3.4+ and above. With the switch to kali rolling we are starting to see errors inside chroot where the kernel is not able to support loading Kali.
Finding Kernel Sources
One of the reasons why Nexus was chosen is because all kernel sources are made available through Google's own website. Finding sources can be easy or difficult depending on the manufacturer. A good resource is usually the XDA forums as someone else has probably already built a working kernel and they must provide the sources under GPL. Most kernel development pages on XDA must provide a link to their sources.
Making a Test Kernel
Assuming you don't have a toolchain downloaded already, you can download it by running the following commands: