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

Ensure your phone is charged to at least 15% (ideally higher) to prevent shutdown during the process.

To prevent your phone from immediately updating back to the version you just left: Go to .

Flashing firmware carries a risk of permanently damaging your device. Proceed at your own risk.

This is the standard official method for ZenFone 5 (ZE620KL) users wanting to downgrade from Android 10 to Android 9.

Zenfone 5 Firmware Downgrade Apr 2026

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

Ensure your phone is charged to at least 15% (ideally higher) to prevent shutdown during the process.

To prevent your phone from immediately updating back to the version you just left: Go to .

Flashing firmware carries a risk of permanently damaging your device. Proceed at your own risk.

This is the standard official method for ZenFone 5 (ZE620KL) users wanting to downgrade from Android 10 to Android 9.