How to Root/Unroot Mi4i Without Losing Stock Recovery [Simplified]

Hi Guys,

Are you confused about how to root again after a latest update ?
or Don't know how to unroot again to flash stock ota updates ?
Why so?

P.S. Rooting procedure will be the same after any ota update. You just need to follow it again.
I have tried here to make this process as simple as I can.
Although using Root Tool Package is also a good thing but it doesn't provide any option to Hotboot twrp recovery rather than flashing it.

[ Requirements ]

1. Mi 4i handset & PC/Laptop with USB drivers & adb+fastboot installed. (Don't have ? Take them from here)
2. TWRP Recovery
3. Latest SuperSU.zip

[ Prerequisites ]

Please Enable USB Debugging - On your phone go to Settings > About phone > Tap on MIUI Version several times. 
This will enable Developer options. Now go back to Settings > Additional settings > Developer options > Enable USB debugging.

[ How to Root ]

1. Put SuperSU.zip in the internal memory of your handset.
2. Reboot into bootloader/fastboot mode by
        Switch off phone. Press and hold the VOLUME DOWN button and turn on the handset.
3. Now open the folder in which you have the TWRP recovery image file. Press and hold SHIFT key and press right click button and select Open command window here.

[ Now you have two methods : ]
(1) Temporary Recovery Method : In this method the recovery will not be flashed, i.e. This will notreplace your stock recovery.

Copy this line and paste it in the command prompt by right click and select paste.

• fastboot boot twrp.img

• Wait some seconds. The device will now restart into recovery.
• Select install update from zip and select SuperSU.zip from your sdcard.
• Finally restart the device and enjoy root.

(2) Permanent Recovery Method : In this method the recovery will be flashed on your existing stock recovery, i.e. This will replace your stock recovery.

Copy this line and paste it in the command prompt by right click and select paste.

• fastboot flash recovery twrp.img

• Unplug the usb cable and start the device into recovery mode by :
  Press and hold Volume UP + Power on button.
• Wait some seconds. The device will now start into recovery.
• Select install update from zip and select SuperSU.zip from your sdcard.
• Finally restart the device and enjoy root.

[ Already Rooted ??? Just want to have TWRP recovery ??? ]

Visit [APP][4.0+][ROOT] Flashify and use this app to easily flash and backup your stuff!
thanks cgollner for this wonderful app.
[ Finally How to Unroot ]1. Open SuperSu app on your device.
2. Go to settings
3. Select Full Unroot.

You are fully unrooted now. 
Enjoy.

Credits :
A very very Big thanks to @magdag for recovery
Chainfire for SuperSU zip
@Atyant for the thread from which I have taken TWRP
Me for writing this