This is a very simple video tutorial on how to easily root your Blackview Crown or any MT6592 smartphone with Android KitKat 4.4.2 OS.
3 simple steps to follow
1. Download latest version iRoot v.1.8.2 tool from here or Kingo Android Root, then install it on your PC.
2. Enable 'USB Debugging' on your device. For that go to 'Settings' --> 'Developper Options' and enable (check) 'USB Debugging' option. To enable 'Developper Options' go to Settings > About phone > Build number, once you’ve found the Build number section of the settings, tap on the it 7 times.
3. Connect your smartphone to PC via USB cable; run iRoot or Kingo Root, wait for it to recognize your device and then press on 'Root' green button. Your phone will reboot and then you have to look for SuperUser app and run it. Go to Play Store and install SuperSu. Run it and uninstall chinese SuperUser. You can also uninstall the chinesse application (iroot daemon) installed on your smartphone. Kingo Android Root will install directly the SuperSu application.