Zenfone 5 Firmware Downgrade -

Type adb sideload [filename].zip (where [filename] is the name of your downloaded firmware).

Visit the ASUS Download Center and search for your model (e.g., ZE620KL). Look for the specific "Downgrade to P" (Android Pie) image. Zenfone 5 Firmware Downgrade

Hold simultaneously. Release when the phone vibrates. Flash Firmware: Type adb sideload [filename]

Older versions (like the T00F/T00J) may require using a PC with ADB (Android Debug Bridge). Zenfone 5 Firmware Downgrade

Use volume keys to navigate to and press Power to select. Select your downgrade file.