Hi, the image file that the .zip contains is "chrootable", so it can be used via a vnc viewer (I use PresenceVNC), so it is not necessary to install it via U-Boot. If you want graphical interface, you have to install vncserver on kali, /EDIT (2015.11.03): As you may noticed, there is Kali 2.0 and the repos have changed to sana. Because of this you cannot install anything with the stock repos. If you change your sources.list to sana it may break your kali 1.1.0 distro so be careful!