This file was made originally for Ainol Novo 7 Crystal tablet, but it works (or should work) on all devices based on the following platform:
AML8726-MX System-On-Chip, AMLogic Meson6 gXX costumer platform
Cortex A9 Dual-Core CPU @ 1.5Ghz
Dual-Core Mali400 GPU
Android ICS 4.0.4 or JB 4.1.1
Other exploits have been tried, like Bin4ary's method, Doomlord's method, SRS Root, One Click Root, but all of them can't seem to work (for now) for these devices when Android ICS 4.0.4 or Jelly Bean 4.1.1 is present. So, if you own one of these devices, use this file to gain Root access.
1 - Put the zip file on the root of your SD card
2 - Reboot to recovery (with the device off, press the Vol - and Power button together until it enters recovery)
3 - Select (using Vol keys) "apply update from EXT"
4 - Select the file and run it pressing the Power button
5 - Reboot your device
You should see before Android finishes loading a small notification saying "Android is updating", and after it finishes loading, if you go to the App drawer, you should see SuperSU installed.
It seems that some of these devices that come with newer versions of Android have EXT4 FS instead of UBIFS.
XDA Member Lannig has managed to edit the META-INF file of the "Crystal-Root.zip", re-compress it and re-sign it.
With his permission, and by suggestion of XDA Member AbliB, i'm posting Lannig's root file here in the OP, so that users with these AmLogic devices with EXT4 File System can have root.
Credits for the original root file (Crystal-Root.zip) go to Soulflier @ Slatedroid.com
Credits for the alternative root file go to Lannig @ XDA