I’ve seen quite a few posts in the Internet about people who are trying to set various options in /boot/config.txt in Kali. This file is the “bios”, and simply creating it has no effect. The reason is easy, your Kali install (if you used the RPI Kali download from Offensive Security) has 2 partitions: /dev/mmcblk0p1 (boot partition), and /dev/mmcblk0p2 (normal file system). Now, /dev/mmcblk0p2 has a folder “/boot/”, but THIS IS NOT the correct folder, even though it is titled correctly. The correction is simple:
mkdir /fat32 mount /dev/mmcblk0p1 /fat32/ nano /fat32/config.txt umount /fat32
This will create a folder called fat32 (in effect, this is equivalent to the /boot/ folder, but w/o a name collision). Now just write your config changes into /fat32/config.txt, and unmount the filesystem just to be safe. Keep in mind fat32 is an arbitrary name, so feel free to call it whatever you want. Your desired settings will be working! You will more than likely want to follow http://rageweb.info/2013/11/07/vcgencmd-on-kali/ to install vcgencmd to ensure the settings were applied.