Even though the Sony Xperia Arc S will not receive the official Android Jelly Bean flavor (the ICS 4.0.4 OS is the top Android version that can be OTA received), you can still test and run the latest OS released by Google and this by learning how to update your phone with a custom ROM firmware. Well, if I have aroused your interest then you will probably want to check the next step by step guide; by completing the same you will update the Xperia Arc S with CM 10.1 custom ROM and install the Android 4.2.1 software on your handset.
So after applying this tutorial you will be able to enjoy the latest Android Jelly Bean features on your own Arc S, not to mention that many other features (that cannot be found in the default version of the Android platform) and apps will be added to your device. Unfortunately this is not the official CM 10.1 software therefore not all the features will work for your Xperia Arc S. We are dealing with the alpha 2 build version of the CM10.1 OS, so there are still bugs into the system. Don’t worry though, as the problems will be resolved as soon as a new variant of the update will be provided.
Anyway if you want to learn more about this update, you can check our source page from here. Then, return here and resume the rest of the lines for learning in how to install the CM 10.1 Android 4.2.1 custom ROM firmware on your Sony Xperia Arc S. Before going any further you should backup the data (messages, call logs, market apps, contacts, calendar info and so on) which is being saved on the internal storage memory of your device. A Nandroid backup might also be a good idea. A full wipe of the system will have to be performed so the backup is exactly what you need.
Then, you must continue by unlocking the bootloader and by rooting your Xperia Arc S. A custom ROM, such as CM 10.1 can be installed only on an unchained system and the only way for removing the factory restrictions and settings will be by performing the mentioned operations. You should follow and apply suitable tutorials for applying the root and unlock bootloader tasks because the warranty will get void, meaning that you can end up in bricking your smartphone. Those who will need the warranty back will have to downgrade to the stock Gingerbread 2.3 OS.
Up next you need to read and complete the next pre requisites. I have mentioned the same during the following list, so don’t skip this section.
Install a custom recovery image (such as CWM recovery) on your phone. This tool can be installed only on a rooted OS; also you will not be able to update your Xperia Arc S to Android 4.2.1 without using CWM recovery.
Then, a Windows running computer will be required. Uninstall all the security tools and settings that are being running on your computer and smartphone as these tools are usually interfering with the update operation.
Check the battery status on your handset and if there is less than 60% power left charge the battery before heading to the proper steps.
Enable the USB debugging option by going to “Settings -> Applications -> Development -> USB debugging”.
And do not install the CM10.1 Android 4.2.1 Jelly Bean firmware on any other device similar with the Sony Xperia Arc S as this guide can be applied only for the mentioned phone.
How to Update Xperia Arc S to Android 4.2.1 Jelly Bean with CM 10.1 Custom ROM Firmware
Download the update file from here and the Google Apps package from here.
Place the files on your computer.
Then, connect the Arc S with the PC via USB cord.
Select the downloaded files and copy-paste them from the PC to the phone’s SD card.
Then turn off the handset.
Reboot it in recovery mode.
From the recovery mode menu select “wipe data factory reset” and “wipe cache partition” (do the backup before applying this step).
Next, select “install zip from sd card” followed by “choose zip from sd card”.
Pick the update file, install the same and repeat the operation for flashing the Google Apps package too.
When the installation procedure is over you will have to wipe the system once more (select “wipe data factory reset” and “wipe cache partition”).
In the end select “+++go back+++” and end the process by selecting “reboot system now”.
Congratulations, you have managed to safely update the Sony Xperia Arc S with the Android 4.2.1 Jelly Bean based CM 10.1 custom ROM firmware. Take note that this is not the stable or official version of the CM10.1 software so there are bugs and things that aren’t working in the system. Therefore test the new ROM and see how it performs; share the issues with us and with other users as well. And if you don’t like the CM10.1 platform, then you can reboot in recovery mode again and restore the stock ROM (if you have previously saved it).