Last month Sony rolled out Android 8.0 Oreo update for Xperia XZ Premium (G8141) and now Xperia XZ F8331 variant starts getting the Oreo update with build number 41.3.A.0.401. The Oreo update starts rolling out through OTA (over the air), which will reach on all devices within a week or more. Alternatively, experienced users can download the Android 8.0.0 build 41.3.A.0.401 firmware (FTF file) and flash manually on Xperia XZ F8331.
Android 8.0 Oreo update (build number 41.3.A.0.401) includes various new features like Xperia Actions, Autofill, Smart text selection, App shortcut, Reminders, latest Android security patches (November 2017), optimizations and general bug fixes. If you own Xperia XZ or Xperia XZs and did not received the OTA notification, you can download and install the update manually.
To install the Android 8.0, build 41.3.A.0.401 manually, your device should be running on build number 41.3.A.0.401. First of all, check your firmware version. If you are on latest version, then proceed with the manual installation.
Note that the full firmware file (FTF file) for Sony devices can be downloaded directly from Sony’s servers using the XperiFirm tool. Interested users can download the XperiaFirm tool from XDA [HERE] and download latest version of the FTF firmware file for your device. Do not forget to select correct device and region before downloading.
Important: We recommend OTA update method, as the manual method is risky. Back up all data before manually installing the firmware on your phone.
Disclaimer: Follow the instruction at your own risk. We will not be liable if any damage occurs to your device and/or its components. Inexperienced users should not proceed with below steps.
1. Download Android 8.0 Oreo firmware file, build 41.3.A.0.401 (FTF) for Xperia XZ [HERE] or use XperiaFirm tool
2. Download latest version of Sony firmware Flashtool [HERE] and install it on your PC. It will create a folder named Flashtool in your C drive.
3. Enable USB Debugging option on your Xperia phone (Settings -> Developer Options -> USB debugging)
4. Copy the downloaded FTF file to the folder “Firmware” inside the Flashtool folder
5. Now, run the Flashtool, select the FTF file and press OK.
Important: If you do not want to delete user data, just uncheck flashing userdata.sin file (we do not recommend it, as it may create additional issues)
6. Turn off your phone and when Flashtool prompted to connect your device, connect your phone to the PC by pressing Volume Down button on the phone. This will connect the phone in flashmode.
7. Wait for until the update installs and then reboot your phone.
You have now successfully flashed Android 8.0 Oreo firmware on your Xperia device. Enjoy! (Source)