Kali Linux on the Raspberry Pi: 3, 2, 1, and Zero (ZDNet)
The installation images are available on the Offensive Security ARM Images Downloads area, where you will find custom images not only for the Raspberry Pi, but for a variety of other ARM SBC systems (Beaglebone, BananaPi, etc.) and even ARM-powered Chromebooks from HP, Samsung and Acer. The really exciting news for me, though, is that there are images not only for the Pi 2/3, but also for the original Pi."
