Highly recommended, it works like a charm!

A demo video exists on YouTube.

http://www.wugfresh.com/brt/

My tablets are both:

• Lenovo A5500-F
• Version Android 4.4.2
• Version Kernel 3.4.67
• One with Build Number A5500F_A442_000_027_141207_ROW
• One with Build Number A5500F_A442_000_029_150408_ROW

Here is the procedure (described with images and further details everywhere on the web)

First, configure the tablet to be able to connect onto it from the PC:

• Enter the “Settings”
• Select “About phone” (at the very bottom)
• And press 7  times “Build number” to enable the developer mode

• Go back to the “Settings”
• Select “Developer Options” (now above “About phone”)
• In the part titled “Debugging”, tick the option ‘USB Debugging’ and answer OK if prompted to confirm

Now Plug the tablet into the PC and Run “Kingo Root” on the PC:

• Kingo Root starts with the message “Not Connected”.
• Then it immediately continues with “connecting…”
• And finally it displays the name of the connected device “LENOVO A5500-F” with the messages “Mode Normal”, “Root Status : No”
• On the tablet, you see a picture with “Kingo Root” and the message “USB connected”
• If you have a prompt from the tablet to authorize the PC to connect on the tablet, accept it

You are ready to start rooting the tablet!

• Press the Button “Root” in “Kingo Root”.
• It starts to root the device. On the tablet, you see the message “Rooting…”
• After a few minutes, the tablet will reboot automatically a first time (you will hear the sound of disconnection/re-connection on the PC). Wait until “Kingo Root” redetect the tablet. As soon as rededected, it will check that it’s well rooted. During that operation, the picture with “Kingo Root” reappears on the tablet.

If you see a prompt from Google on the tablet, to check that the device has no security issue, just refuse it.

After the first reboot, “Kingo Root” saw that my device was not yet rooted and it continued with installing more stuff… Soon later, the tablet rebooted again automatically and “Kingo Root” restarted the same process. Concretely, it did the same routine 5 times (I.e. it rebooted five times) before announcing that the device was successfully rooted.

Something weird however… Although Kingo Root” pretended that the device was rooted, “Root Checker” told me it’s not the case ?!

I did restart “Kingo Root” and pressed “Root Again”. It did some updates but didn’t reboot automatic and Bingo ! “Root Checker” now confirmed that it was rooted.

NB.: you should be prompted to confirm that “Root Checker” may be granted Root Access by KingoUser.

It took me a bit more than 30 minutes.

NB.: Later, I did update the device with Build Number A5500F_A442_000_027_141207_ROW to Build Number A5500F_A442_000_029_150408_ROW and I had to re-root the device! It went fast and without any reboot. (NB.: I had to accept again to grant Root Access to Root Checker for KingoUser).