If you are a Zenfone 5 user, we have a happy news for you, Android 5.0 Lollipop update is available for the Asus Zenfone 5, officially. The update is available for A500CG and A501CG variants of the phone.
Before you upgrade
Please note that Android 5.0 Lollipop does not support some pre-installed apps. The listed apps below will be removed once the Android 5.0 Lollipop upgrade is complete. The update and installation will take some time.
1. Battery widget
2. PhotoFrame widget
3. Google Text-To-Speech
4. Movie Studio
5. Cloud Print
6. CMClient
7. Magic Smoke Wallpapers
Before upgrading make sure you check the system update on your phone and Upgrade it to the latest available firmware.
How to update your Zenfone 5
If your phone do not show the upgrade, you can do it manually. Download the firmware update Version WW_3.23.40.52(android L) from the Asus Support page (under firmware), download size is 700MB, and copy it to the phone’s internal storage and remove the data cable. Phone will pop up an upgrade information, tap on that and choose the upgrade.
How to downgrade your Zenfone 5 to Android 4.4.2 Kitkat
If you want to downgrade to KitKat after updating to Lollipop, You may downgrade your Asus Zenfone 5 too. For that you need to download two files from the above link, Version TW_5.3.3.3 (Downgrade Version-2) and Version TW_5.2.2.2 (Downgrade Version-1)
1. Download the downgrade tool: UL-ASUS_T00F-TW-5.3.3.3-user.zip/UL-ASUS_T00F-TW-5.2.2.2-user.zip
2. Using MTP connecting ZenFone5 with PC. (Enable MTP: Setting-->Storage-->press the USB icon on right corner--> Enable MTP)
3. Copy file UL-ASUS_T00F-TW-5.3.3.3-user.zip to the ZenFone5 internal storage.
4. Remove the USB cable, the device will pops up the system upgrade information.
5. After finished, device will auto reboot and perform factory reset.
6. Then copy file UL-ASUS_T00F-TW-5.2.2.2-user to the ZenFone5 internal storage again.
7. After downgraded, device will auto reboot and perform factory reset.
8. After finished, please go to Settings->About-> software information->Build number. The version should be V2.21.40.44
Zenfone 4 (A400CG and A450CG)
Please notice that below new apps will be added in this system upgrade.
1. TripAdvisor
2. Gameloft
3. CleanMaster
4. Zinio
5. ASUS Auto-start Service Manager
To upgrade your Zenfone 5
It is just like the Asus Zenfone 5 upgrade, Get the file Version WW_7.3.3 (Android L) from the Asus Zenfone 4 support page. The page also have instructions to downgrade Zenfone 4 to Kitkat from Lollipop too.