Now you can easily root Sony Xperia S via the Eroot Rooting Toolkit. Just run the toolkit. Then root it. That’s all. Simple, right? Yes, with the correct tool and drivers. It is not mission impossible to do so. This method work on firmware 6.1.A.2.55, 6.1.A.2.50, 6.1.A.2.45. Both Locked/Unlocked bootloader.
Warning!!
– Rooting void your device warranty. If your device damaged or malfunction by following this tutorial, I can’t claim its damages. Applying this method at your own risk. But this is not a risky process.
– Charge your battery to decent levels so that your phone doesn’t shut down amidst the process
How TO ROOT Sony Xperia S
– Install drivers for your phone PC Companion
– Download and Extract the root tools zip file Or this link
– Now run the Eroot rooting toolkit and if it says to download that 10mb file then just click on that green button to cancel it.
– Enable USB debugging and unknown resource on your device.
– Now connect your Sony Xperia S to your computer using usb cable and on the computer screen inside the Eroot window click ?root.
– the rooting process will start immediately and will finish with a message of success. When it displays “ROOT”.
– You can verify your Xperia S rooting by running the famous app that tells you whether your android device is rooted or not.You only need to download and install Root Checker from Google Play Store and run, just tap the button Do I Have Root? and app will tell you the result.
Source: XDA