Sony has been true to its word regarding the long-awaited Ice Cream Sandwich updates. One of the few lucky candidates from its Xperia 2011 portfolio to receive the Ice Cream Sandwich update is the Sony Ericsson Xperia Arc S LT18i. With its 1.4 GHz processor, 4.3 inch touchscreen, and stylish metallic design, adding Ice Cream Sandwich to the mix is certain to be a match made in heaven.

However, Sony has planned to release the software update by regions instead of a worldwide release. But, luckily for us, the folks at XDA Developers were able to make a flashable file that can be installed using Flashtool.

So, if you have been desperately waiting for months for the Ice Cream Sandwich upgrade, then check out our guide below on how you can install it on your Sony Ericsson Xperia Arc S.

Requirements

• Sony Ericsson Xperia Arc S (LT18i)
• A Windows PC
• Enable USB Debugging on your phone. You can do this by heading to Settings > Applications > Development > USB Debugging. Make sure that there is a check mark beside that option.
• Back-up of your personal files and important data. You can read our guides on how to backup your data locally and how to backup your data to the cloud.

Instructions

Installing Flashtool and Xperia Arc S drivers

1. Download Flashtool 0.7.1.0 from here (flashtool-0.7.1.0-windows.exe, MD5 : 4A91DB666201BE1AFF58F3AF3847B050) and install it on your computer.
2. Head to the Flashtool folder at C:\Flashtool and open the drivers folder. Double-click the Flashtool-drivers.exe file to start installing the essential drivers for your phone.
3. In the driver section of Flashtool, click Nextonce. When prompted for a component selection, choose the following options:
   • Arc-Play-Neo-Acro ADB Drivers
   • Flashmode Drivers
4. Select Next to start installing the necessary drivers. Once the installation process has started, you’ll be bombarded with lots of pop-ups saying that the drivers are not compatible on your PC. Select Install this Driver Anyway on each of the pop-up screen.

Installing the ICS firmware

1. Download the official ICS firmware (LT18_4.1.A.0.562_NCB.ftf, md5sum: c1ae2eef1677a7aa72db7430e516ea4c) file for the Xperia Arc S from here and save it to your PC.
2. Place the downloaded FTF file inside the c:\Flashtool\firmwares folder.
3. Double-click the FlashTool.exe file found inside the Flashtool folder to start the flashing program.
4. As soon as the Flashtool program opens, click the Flash button from among the first seven buttons found on top of the screen.
5. Select Flashmode on the screen that pops-out, then select OK.
6. You will then see LT18i from among the list of devices in a new window that shows up.  Select the LT18i entry on the list. Check the box beside the label “No Final Verification Check.” Also check the boxes for “Wipe Data” and “Wipe Cache.”
7. Hit the OK button.
8. Connect your Xperia Arc S to your PC via the USB cable. Plug your USB cable to your PC first. Press and hold the Back key on your phone and connect the other end of the USB cable to your phone.
9. Once your phone is connected, the Flashtool application will automatically start the flashing process.
10. Important! Once the flashing process is done, you may sometimes get an error message saying “Error Flashing”, instead of the “Flashing Complete” message. Ignore this error as it may be a bug in the application. Your firmware should already be flashed on your phone.
11. Disconnect your phone from your PC.
12. Switch on your phone. On your first boot, your phone may restart once at the Sony Logo, then it will normally boot into Ice Cream Sandwich.

Congratulations! You have successfully updated your Xperia Arc S LT18i to the official Android 4.0 Ice Cream Sandwich update.