How to root Android 4.0 ICS firmware 4.1.A.0.562 For Sony Ericsson Xperia Arc S LT18i

                      The Sony Ericsson Xperia Arc S LT18i is truly living up to its name for having a lightning-fast 1.4 GHz processor while remaining slim and sexy. It’s no wonder that it is one of the first Sony devices to experience the Ice Cream Sandwich update.
The official Ice Cream Sandwich (ICS) update for the Xperia Arc S can both be rewarding and could also be dreadful considering you would eventually lose root privileges if you flash it on your device. Rooting can be a dangerous practice since a single mistake could spell disaster and possibly brick your device.
Thankfully, you can now root your device thanks to XDA Developers member DooMLoRD for repacking a script that perfectly works with the Xperia Arc S model. Check out the guide below for the full story.

Requirements

• Sony Ericsson Xperia Arc S (LT18i) running Ice Cream Sandwich firmware version 4.1.A.0.562 with locked or unlocked bootloader.
• Windows PC
• ADB drivers installed on your computer (Flashtool-drivers.exe, md5sum: 3ceff17ea876b403441bb54092d9d00a)
• Enable USB Debugging on your phone. You can do this by heading to Settings > Developer Options > USB Debugging. Make sure that there is a check mark beside that option.
• Enable Unknown Sources on your phone. You can do this by heading to Settings > Security > Unknown Resources. Make sure that there is a check mark beside that option.

Instructions

Rooting Xperia Arc S via Fastboot

1. Download the following files and save them to your PC:

   • SuperUser Package file (Superuser-3.0.7-efghi-signed.zip, 625 KB)

   • ARC-DooMKernel file (ARC-DooMKernel-ICS-BETA-v04-lower-boot.img, 7.6 MB)

   • Fastboot (Fastboot.zip, 404 KB)

2. Connect your Xperia Arc S to your PC via the USB cable.
3. Copy the Superuser-3.0.7-efghi-signed.zip file to the root of your phone’s SD card.
4. Disconnect your phone from your PC.
5. Extract the Fastboot.zip file and place it in the C:\ directory on your PC. You should extract a folder named Fastboot with four files inside.
6. Copy the ARC-DooMKernel-ICS-BETA-V04-lower-boot.img file and place it in the Fastboot folder. You should have 5 files by now in the Fastboot folder.
7. Connect your Xperia Arc to your PC but this time around you must be in Fastboot mode. You can do this by first plugging your USB cable to your PC. Hold the Menu key of your phone then connect the other end of the USB cable to your phone.
8. On your PC, launch the Command Prompt from Start > All Programs > Accessories.
9. In the Command Prompt, enter the following commands and hit the Enter key after each command:
   • cd c:\Fastboot
   • fastboot boot ARC-DooMKernel-ICS-BETA-v04-lower-boot.img
10. Important! Once the kernel has been flashed, your phone should automatically reboot itself. As soon as the Sony splash screen shows up and the blue LED lights up, press the Back button repeatedly on your phone to enter ClockworkMod Recovery.
11. In ClockworkMod Recovery, select Install ZIP from SD Card.
12. Select Choose ZIP from SD Card then browse for the downloaded Superuser-3.0.7-efghi-signed.zip file and select it. Confirm the installation by selecting Yes on the screen that follows. It may take 2-3 minutes for the installation process to complete.
13. Head back to the main recovery menu by pressing the Back button on your phone.
14. Select Reboot System Now to reboot your phone.
15. Complete the rooting process by installing BusyBox on your phone, as it is required by many applications to use root access properly. You can install BusyBox by downloading the app from the Google Play Store.
16. Launch the BusyBox Installer app on your phone and select the Allow button to grant the application root access. Select Ok when a pop-up screen shows up. Select the Install button at the bottom to download and install BusyBox on your phone.

Rooting via one-click method

1. Download the Rooting Toolkit for the Xperia 2011 ICS (DooMLoRD_v1_Xperia-2011-ICS-ROOT-emu-busybox-su.zip, MD5HASH: dc7f4a107e7d991572219404a9ca996e) from here and save it to your PC.
2. Extract the downloaded file using any extracting software and place them inside a folder.
3. Connect your phone to your PC via the USB cable.
4. Double click the runme.bat that you obtained during extraction. This will also begin the rooting process.  Wait for the application to finish rooting your phone.
5. After a while, you should be greeted with an “All Done” message. Your phone is now rooted.
6. Disconnect your phone from your PC.

Congratulations! You have successfully rooted your Sony Ericsson Xperia Arc S LT18i running Ice Cream Sandwich firmware 4.1.A.0.562.