Android 5.1 Lollipop
How to update Xperia Z (Yuga) to Android 5.1 Lollipop via unofficial OmniROMYouMobile

Sony is yet to announce the release of the highly-anticipated stock Android 5.0 Lollipop update for the Xperia Z codenamed Yuga, while industrious XDA recognised developer, Olivier, has already rolled out the latest Android 5.1 update for the flagship phone via the latest unofficial or experimental OmniROM.

The Xperia Z can now be updated to Android 5.1 via Omni ROM, which was released on the XDA forums on 29 March. As the ROM is still under development, it may harbour a few untested bugs or broken features that will be fixed in the upcoming updates.

The complete changelog and Bugtracker are available via the official OmniROM developer portal.

Nevertheless, those who want to get a glimpse of the Android 5.1 Lollipop update on their Xperia Z ahead of the official firmware release can go ahead and install the CM12.1 based Lollipop ROM on their device, using the step-by-step guide provided below.

IBTimes UK reminds readers that it will not be held liable for any damage to device during or after the ROM installation. Users are advised to proceed at their own risk.

Pre-requisites

  • The instructions given in this guide are meant for the international variant of Xperia Z only. Verify device model number by navigating to Settings > About Phone
  • Ensure the phone has at least 80% battery charge to prevent unexpected device shutdown (due to battery drain) while installing the ROM
  • Back up data and settings using a recommended custom recovery tool, like ClockworkMod (CWM) or TWRP, as it creates a complete image of the existing phone setup. In Recovery, choose Backup and Restore and tap Backup
  • Verify correct USB drivers for the phone are installed on the computer (download Xperia Z USB drivers)
  • Enable USB Debugging mode via Settings > Developer Options (if running Android 4.0 or above) or Settings > Applications > Development (if running Android 2.3 or earlier)
  • Ensure that the device is rooted with CWM recovery installed and its bootloader is unlocked

Download Required

Android 5.1 Experimental OmniROM for Xperia Z (aka Yuga)

Google Apps

Steps to Install Android 5.1 OmniROM custom ROM on Xperia Z

Step 1 - Download OmniROM Android 5.1 Lollipop ROM for Xperia Z on the computer.

Step 2 - Connect and mount the phone's USB mass storage on computer with the USB cable.

Step 3 - Now, copy the downloaded OmniROM zip file to the root folder on the phone's SD card.

Step 4 - Power off the phone and disconnect its USB cable from computer.

Step 5 - Now boot the device into Recovery Mode by tapping Volume up or Volume Down buttons when the phone'snotification LED turns pink.

Step 6 - Once the phone enters into CWM Recovery, perform a full data wipe task by clicking Wipe Data/Factory Reset. Use the Volumekeys to navigate between options and the Power button to select an option in the Recovery Mode.

Step 7 - Then, perform Wipe Cache Partition and wait until the process completes.

Step 8 - Now perform Wipe Dalvik Cache as well. To do this, go to the 'advanced'option and then click Wipe Dalvik Cache. This will help in preventing boot loop issues or any boot ROM related errors during firmware installation.

Step 9 - Then return to the main recovery menu and choose Install Zip from SD card.

Step 10 - Now click Choose Zip from SD card. Use volume keys to navigate to the OmniROM zip file that you copied earlier to your phone's SD card and choose it by tapping the Power button. Confirm the ROM installation on the next screen and the installation process will begin.

Note: Repeat Step 9 and Step 10 to installGoogle Apps (Gapps) as well.

Step 11 - Once both the Gapps and ROM are installed, go to "+++++Go Back+++++" and select Reboot System Now in the Recovery menu.

The phone will now reboot and the first boot may take about five minutes to complete. So, please be patient.

Your Xperia Z is now running the latest Android 5.1 Lollipop via OmniROM custom ROM. Go to Settings > About phone to verify the firmware version installed.

[Source: XDA]