Three of Sony’s older smartphones can be updated to Google’s latest operating system. The owners of the Xperia Z1, Z1 Compact and Z Ultra can get the 6.0 Marshmallow via an unofficial ROM, which means that it was developed by the Android community. It seems that Sony has ended support for these models, disappointing many fans, but luckily, the Android 6.0 Marshmallow update image we’re telling you about works great.
The AOSP ROM has only a camera bug and it affects the Z Ultra and Z1 Compact phones, while the rest of the features, such as the WiFi, Networks and calls, Brightness, Display, Bluetooth or Orientation and Ambient light sensor, don’t have any problem.
So, if you own one of the three Sony handsets, you’ll need to look on the internet for the Android 6.0 Marshmallow AOSP ROM especially for your type of model, then get the Google Apps and the SuperSU root package from Chainfire.
Make sure that the battery of your phone has 80 percent left of juice, so it won’t shutdown during the installation of the ROM. You will need to back up data and settings using TWRP or ClockworkMod (recovery tool), so in Recovery, select Backup and Restore, then tap Backup.
Install the right USB drivers on your computer, for your phone, then go to Settings > Developer Options to enable USB Debugging mode, if your device runs on Android 4.0. If it runs on Android 2.3, you’ll find this option in Settings > Applications > Development. The phone must be rooted with CWM or TWRP installed, because you will need one of these recovery tools to install Gapps. Also, bootloader must be unlocked.
Now, prepare for the installation of the Marshmallow ROM, which you’ve downloaded from the internet, along with Google Apps. Create a folder on your computer with the name “update6”, which will contain these four files: system.img, cache.img, boot.img and userdata.img, which you’ll copy to it.
Then, connect your phone to your PC and after copying the Gapps file to a folder, disconnect the device and boot it into bootloader mode. For that you’ll need to download Quick Boot app from the Google Play Store. While you’re in the update6 folder, launch the command window, press the Shift key and, in the same time, right click on an empty space (it’s white). When the context menu pops up, select Open and you’ll see a command window with a location path which will point to the update6 folder.
After that, you will run these commands, in this order: fastboot flash boot boot.img;
fastboot flash cache cache.img; fastboot flash system system.img; fastboot flash userdata userdata.img and fastboot reboot.
After the phone boots up, go to Settings > About device, where you’ll confirm that you’ve installed Android Marshmallow. Finally, boot into recovery mode and tap on the Backup option to backup your data and choose all partitions, to start the backup process, swipe from the bottom of your screen. The last step is to install Gapps and then return to the TWRP recovery home screen, where you’ll tap on Install and after locating the Gapps file, just tap on it and swipe again from the bottom of the screen. The app package will start flashing and when Gapps completes installation, restart your device by tapping on the Reboot system button.