Root Transmission: Root your Android device by tethering… to another Android device
There are tools available to root nearly every Android phone or tablet released to date. Many of those tools require you to hook up your mobile device to a PC with a USB cable and run a utility on the PC.
Root Transmission removes the PC from the equation. You can use this app to connect two Android devices together with a USB cable and root one by sending commands across the cable.
Root Transmission requires a rooted Android device with USB On The Go (OTG) support to work. You’ll also need a USB OTG cable to link your devices.
For many users, it’s probably still simpler to just connect the device you want to root to a PC. But if you don’t have a computer handy, Root Transmission presents an interesting alternative. It also demonstrates that basically your phone or tablet is a mobile PC.
Right now the app is capable of rooting a handful of devices including the first generation Amazon Kindle Fire, Verizon Samsung Galaxy S III, international Samsung Galaxy Note II and a few more phones by running the appropriate scripts.
Bear in mind that running the wrong script can break your devices — both of them. So you’ll want to make sure you only download scripts from trusted sources and/or know how to create your own scripts before using Root Transmission.
You can find more details, download links, and instructions at the xda-developers forum.