
Jcase, IOroot, Autoprime and a few other developers have finally released the ultimate root method for the LG G3. Stump root will root all variants of the LG G3 including the Sprint variant which has not been rootable since release. Rooting your device is nearly as easy as towelroot.
-Install the StumpRoot app
-Run StumpRoot
-Reboot when app tells you
-Install SuperSU apk from the play store
-uninstall StumpRoot
-Profit
It should be noted that if you decide to unroot you may have to flash stock firmware to regain root, but may be able to reroot without doing so.
There is also a bruteforce mode for unsupported models.
When Stump hits a device it does not "know" it can bruteforce the location. This can take upwards of 2 hours, but once down (if the phone has an internet connect) it will report it to us, and future builds can include the location.
Via XDA