Use Stable CM 11 Custom ROM To Update A Sony Xperia U

Sony is no longer going to be updating the firmware of their Xperia U. The last update this device got was to Android 4.1 Jelly Bean. If you have an Xperia U and you want to update your device, your now going to have to use a custom ROM.

The CyanogenMod 11 custom ROM can be used on an Xperia U to unofficially update it to Android 4.4 KitKat. In this guide, we are going to show you how.

Prepare your phone:

Make sure that the phone is an Xperia U ST25i. Don’t try this guide with any other device.
Make sure that the phone’s bootloader is unlocked.
Make sure that the phone’s battery is charged to at least over 60 percent.
Back up all you important call logs, contacts, and sms messages.
Back up all you important media content by copying them onto a PC.
If you have a rooted device, use Titanium Backup for your apps and data.
If you have a custom recovery (CWM or TWRP) installed on your phone, use it to back up your current system.

Note: The methods needed to flash custom recoveries, roms and to root your phone can result in bricking your device. Rooting your device will also void the warranty and it will no longer be eligible for free device services from manufacturers or warranty providers. Be responsible and keep these in mind before you decide to proceed on your own responsibility. In case a mishap occurs, we or the device manufacturers should never be held responsible.

How-To: Flash Android 4.4 KitKat CM11 Custom ROM on an Xperia U ST25i:

Download the following:
1. ROM’s zip file .
2. Google Gapps for Android 4.4 KitKat
Place the files you downloaded on the internal or external SDcard of your phone.
Download Android ADB and Fastboot drivers.
Open the ROM zip file you downloaded in step 1 on a PC. Extract Boot.img file.
Place the kernel file that is the extracted boot.img file in the fastboot folder you downloaded in step 3.
When you’ve placed the kernel file into the fastboot folder, open the folder.
Press shift and then right click on any empty area in the opened folder.
Select “Open command prompt here” and flash it using the following command:

Fastboot flash boot boot.img

Boot your phone into CWM recovery, you can do so by turning your phone off then turning it on and pressing the volume up and down keys.
When you are in CWM, wipe factory data, cache and dalvik cache
Select Install Zip> Choose Zip from SDcard/external SDcard.
Select the ROM zip file that you placed on your SDcard in step 2.
The ROM should flash and when it’s through, select Install Zip> Choose Zip from SDcard/external SDcard again.
This time, choose the Gapps.zip file you placed on your SDcard in step 2. Flash it.
When flashing is done, go to CWM again and wipe the cache and dalvik cache again.
Reboot the system. You should see the CM logo on your boot screen. It could take as long as 10 minutes, but you should eventually see the boot screen become the home screen.