If you have been waiting for the developers to gain root access on AT&T Sony Xperia Ion, then your wait is over now. The developers over at XDA have gotten the root access on the said smartphone and you can too get it by following the steps described below. Just follow each step carefully and at the end, you will have a rooted smartphone.
1. You must have unlocked bootloader of your smartphone. You can do so from here.
2. Rooting your phone will void its warranty. However, you can install stock firmware or unroot your phone to get back the warranty.
1. Download the Insecure Kernel from here. (Download the one which is appropriate for your device)
2. Download the Rooting Package from here. (Download link is there in the first post)
3. Download the Fastboot package from here.
1. Download and place all the files onto your Desktop.
2. Extract files from the Fastboot package to your Desktop.
3. Turn OFF your smartphone using the Power button.
4. Reboot your phone into the Fastboot mode. To do so, press and hold Volume UP+Power buttons simultaneously.
5. When your phone enters Fastboot mode, connect it to your PC.
6. Open a Command Prompt window on the Desktop of your PC and type in the following commands:
fastboot flash boot filename.elf (replace filename with the file you downloaded)
7. After it has finished installing Insecure Kernel, disconnect your phone from the PC.
8. Reboot your smartphone.
9. Enable USB debugging on your smartphone by heading to Menu>>Settings>>Applications>>Development>>USB debugging, tick-mark the box.
10. Extract files from the Rooting Package to your Desktop,
11. Double-click the batch file (.bat) to start rooting your phone.
12. Once the rooting process has completed, go to Google Play and download Superuser as well as BusyBox apps.
Great job, you have successfully rooted your AT&T Sony Xperia Ion smartphone. Now, head on to the Google Play to download the root-only apps which weren’t working on your phone before.
If this procedure helped you, then please head to the official thread over at XDA Forum to thank/donate to the original developer of this root method !