I'll drop the excerpt for you to go ahead with it and get those stubborn android phone rooted in minutes without much stress from your end.
Just thought I should update you about iRoot – an enhanced software that can root plethora of android phone and devices with or without a computer.Continue Reading.......
iRoot is an improvement on the vRoot software that recorded up to 90% success rate in rooting of android phone and devices.
iRoot was updated to include iRoot apk (iRoot.apk) for rooting directly from your android devices without connecting it to a computer machine and iRoot executable (iRoot.exe) for rooting directly from your PC via a USB connection cable.
Either ways, the iRoot software is a great all-in-one root tool with support for newer and older android devices, even less-popular brands of android phones can be rooted with it.
I already tried it on Gionee, Samsung, Tecno, Infinix and Mercury. You can report other devices in this thread to help others find what phones the iRoot app can root easily.
For iRoot apk, follow this link