What do you thiml about this steps :
"Rooting 4.0.2.A.0.62 (stock Android 2.3.4 firmware)
Rooting an Xperia Arc S running on 4.0.2.A.0.62 is a little more complicated, as it requires you to downgrade your firmware first to stock firmware 4.0.2.A.0.42 using a Generic Global, and not region specific firmware.
Downgrade to stock firmware 4.0.2.A.0.42 Generic Global.
Download the LT18i 4.0.2.A.0.42 Generic Global FTF (Xperia Arc (LT18i)_4.0.2.A.0.42_CE.rar, size: 155.17 MB).
Download Flashtool 0.6.9.1 to your computer and install it according to these instructions.
For Windows users (MD5: 9E6AEAA286FC145FDEBD65F6CC492585): Mirror 1 | Mirror 2
For Linux users (MD5: 0BB12562F21B5291F34CD06272EB10F5): Mirror 1 | Mirror 2
Before you continue, you’ll need to disable your computer’s antivirus software as it interrupts the tool.
Flash the LT18i 4.0.2.A.0.42 Generic Global FTF using Flashtool 0.6.9.1.
Root the phone using DooMLoRD’s Easy Rooting Toolkit.
Download DooMLoRD’s Easy Rooting Toolkit (DooMLoRD_v4_ROOT-zergRush-busybox-su.zip) to your computer.
Extract the file using 7-Zip, WinRAR, or other similar file extraction programs.
Extracting the file should give you the runme.bat file.
Connect your Xperia Arc S to your computer via the USB cable.
On your computer, double click on the runme.bat file to launch it.
Follow the instructions on the screen.
Perform OTA upgrade for 4.0.2.A.0.62.
Do not use the PC Companion to upgrade back to firmware 4.0.2.A.0.62, otherwise root will be lost.
Your Xperia Arc S should now be rooted. You can now continue to installing ClockworkMod Recovery on your Xperia Arc S.
ClockworkMod Recovery
Thanks to pvyParts and nobodyAtall, both recognized developers on XDA Developers, it is now possible to easily install ClockworkMod Recovery 5 on your Xperia Arc S. The Xperia Auto-CWM Installer app appears to be working for both locked and unlocked bootloaders. Download the Xperia Auto-CWM Installer from the Google Play Store and easily install ClockworkMod Recovery on your Xperia Arc S without the hassle of wires or command prompts. The app, however, requires your Xperia Arc S to be rooted and to be running on stock 2.3 software.
If you’d like to read more about the app, we recently wrote an app review for the Xperia Auto-CWM Installer.
Once you’ve installed Xperia Auto-CWM Installer, you’ll see a checklist that shows you the app’s requirements for installing ClockworkMod Recovery. If you’ve accomplished all of the app’s requirements, simply tap Install CWM 5 from the menu."