Warning : I will not be held liable for any damage on your device. It may void your warranty.
For kitkat only JB may not work. Before root kindly backup your data.
You need for this rooting method
1. Root z5 kitkat v2
2. Intel driver
3. USB Cable
4. Windows pc
1. Download first Intel driver on your pc extract it and install it.
2. After installed, connect your phone to your pc using usb cable. Don't forget to enable debugging mode. To do that, go to settings>about>software information>build number (tap 7 times to enable developer option) then, go back to settings>developer options>usb debugging (enable/check it).
3. After update, Test for authorized connection between pc and phone. Go to downloaded rootz5kitkatv2 on your pc and click files>hold shift + right>choose open command window.
4. Then cmd will prompt. Then type " adb devices" hit enter. The left side is your serial number and the right side is the word "device" it means your good to go.
5. If the word "unauthorized" will appear instead of "device" then youre not good to go. So unplugged your phone from pc and reconnect again. A prompt from your phone will appear. Just check allow always to continue.
6. Please read the instructions carefully. These time we will root your phone. Now, stay connected to your pc with your mobile and open the file "rootz5kitkatv2" that you download file. Double click "root-zenfone5-ww" or "Root-ZenFone5-en"
7. The bat file will open and the rooting process is now starting. Your phone will reboot 5 to 6 times. Just press any key to continue. Wait for some more time
last reboot screen ...
8. Last reboot will appear, check your phones app drawer, if you can see SuperSU, congrats! you are now rooted.
9. To survive root access during OTA updates, go to supersu>settings>enable pro. Once done, go back again supersu>settings>enable survival mode.