The Xperia ZL will probably receive the Android 4.4 update officially, sometime in the future, but until that happens, Sony has to release the new OS on its latest devices, such as the Xperia Z1, Z Ultra and so on. As such, it may take a while before Xperia ZL owners will be able to enjoy Google's latest mobile operating system.

Alternatively, you can give a custom ROM a try, and skip the waiting process for the official release. If this sounds like a good alternative, then you can follow this guide in order to apply the latest "nightly" version of AOKP's custom ROM on the Sony Xperia ZL. AOKP is a custom ROM based on Android 4.4 and CM 11, but being still under development, you might encounter certain bugs after the installation. However, Team Kang launches new nighlies in a timely manner, so these potential bugs should be fixed sooner rather than later.

Before proceeding, keep in mind that AOKP comes with vanilla Android UI, and as such, Sony's proprietary user interface will no longer be available.

IMPORTANT – READ BEFORE PROCEEDING:

  • This is a guide and ROM that work only on the Sony Xperia ZL. Don't attempt to install this ROM on any other smartphone as it will probably brick it
  • In order to apply this ROM, you'll need a rooted Xperia ZL with fastboot, and the latest version of CWM or TWRP recovery
  • During the installation process, you will be required to apply a factory reset. It's recommended that you create backups before proceeding
  • Applications such as "Helium", "SMS backup & restore" and "APN Settings Backup & Restore" can be used to backup app data, text messages and APN Internet settings respectively
  • Contacts can be backed up onto your Google account
  • The installation process includes steps on how to create a NANDROID backup
  • Before moving on, you need to enable USB Debugging, as you'll need to connect your smartphone to your computer. To enable the feature, tap "Menu" > "Settings" > "Developer options" and mark the "USB Debugging" check box
  • This is a guide for advanced users and includes unofficial steps. Proceed at your own risk. If you brick your phone or lose important data, you can't hold the developers or anyone else responsible
  • Don't skip any steps and bullet points!

Entering CWM or TWRP Recovery:

IMPORTANT: this is a set of steps allowing you to enter CWM or TWRP Recovery. DO NOT follow this guide at this point. Refer to this guide later on during the installation process, when you'll be asked to do so.

  1. On your Xperia ZL, visit the Play Store and download the "Quick Boot" application
  2. Install the app and open it
  3. Tap "Recovery" in the main menu, and wait for your smartphone to enter wither CWM or TWRP (depending on what recovery you're using)

Sony Xperia ZL – Install Android 4.4 AOKP Custom ROM via CWM Recovery:

  1. Using your computer, download the latest AOKP nightly build available from this link
  2. The ROM does not include Google apps package, so you'll need to download a separate Gapps zip file from this link
  3. Connect your Xperia ZL to your computer via the USB cable
  4. Transfer the two downloaded zip files onto your phone's storage. (Don't unzip the files!)
  5. Once the files have been copied, disconnect your smartphone from your PC
  6. Enter CWM Recovery (refer to the guide above in order to do so)
  7. Now, create a NANDROID backup of your current ROM. This is an important safety measure, so don't skip this step! Select "backup & restore", and create a backup file
  8. With the NANDROID backup created, select "data wipeout / factory reset". You also need to access the "Advanced" menu and select "wipe cache" as well as "dalvik cache"
  9. After you've properly factory reset your Xperia ZL, return to the main CWM screen and select "Install zip from SD card"
  10. Load the AOKP file that you've downloaded at step 1, and flash it
  11. Now, select "Install zip from SD card" again, and flash the Google apps zip file as well
  12. Once both files have been installed, select "+++Go Back+++" and then "Reboot system now"

NOTE: after a fresh ROM installation, the first reboot will take longer than usual. Be patient and don't press any buttons. If the smartphone does not fully restarts in 10 minutes, or if it boot loops, then you need to restart the entire guide. Make sure that you've properly applied the factory reset, and that you haven't missed any steps

NOTE: To restore your previous ROM, you can use the NANDROID backup. Reboot in CWM recovery, select "backup & restore" and then load the appropriate backup file

Sony Xperia ZL – Install Android 4.4 AOKP Custom ROM via TWRP Recovery:

  1. Using your PC's Internet browser, visit this link and download the latest AOKP KitKat nightly build available
  2. You also need to download the Google apps zip file from this link
  3. Connect your Xperia ZL to your PC via USB
  4. Copy the downloaded, unzipped files on your phone's storage
  5. With the files transferred, disconnect your ZL from your computer
  6. Reboot your handset in TWRP recovery (refer to the guide above)
  7. Create a NANDROID backup of your current ROM. Tap "Backup", mark the type of data that you wish to save, give a name to the file and then swipe the "Swipe to Backup" button
  8. After the backup, it's now safe to factory reset the device. Tap "Wipe", go to "Advanced" menu and select "Wipe cache" as well as "dalvik cache". Then, swipe the "swipe to wipe" button
  9. Return to the main TWRP screen and select "Install". Browse for, and select the AOKP zip file
  10. Select "Install" again and load the Google apps zip file
  11. Once both zips have been successfully flashed, return to the main TWRP screen and tap "Reboot"

NOTE: this is the first time you reboot your device after installing the new ROM, so the process can take several minutes to complete. However, if your phone does not restart in normal mode after 10 minutes, or it it's stuck in a boot loop, then you'll need to redo the guide from the beginning. Make sure you haven't missed any steps, and make sure you've fully and properly applied the factory reset.

NOTE: if you need or want to, you can easily return to your previous ROM. To do so, reboot in TWRP recovery, select "Restore" and load the appropriate NANDROID backup

› See More: Sony Xperia ZL: Install Android 4.4 AOKP Custom ROM (Nightly) Using CWM or TWRP Recovery