This tutorial is intended for those who want to downgrade their Asus ZenFone 3 (ZE520KL / ZE552KL) to Nougat from Oreo. After updating to Android 8.0 Oreo, if you found that the new OS is buggy or you want to unroot and return to stock ROM, follow below steps. We will show you where to download stock Nougat firmware for the device and how to install it on the phone with a single click.
Recently, Asus rolled out Android 8.0 Oreo update with build number 15.0410.1712.31 to its ZenFone 3 variants. If you have not received the update yet, you may check this manual installation guide. Oreo update will bring several new features, revamped ZenUI launcher and enhanced system performance to the device.
However, if you do not like this new update for any reason and want to go back to the previous Nougat build, then check out the below guide.
Before start, make sure you’ve backed up all of your important data on the phone. Also, precede care or you will end up with a bricked device.
Downgrade Asus ZenFone 3 from Android Oreo to Nougat
2. Download ASUS Flash Tool from here and install it on your computer.
3. Switch off your phone and boot into Fastboot mode (press Power + Volume Up buttons together).
4. Open ASUS Flash Tool and select your device
5. Browse, and select the firmware you’ve downloaded
6. Now, click on the Serial Number of your device. Click Start.
The process will take 5-10 minutes to complete. After finishing the installation, reboot and enjoy (source –Asus)