How to Unlock ZenFone 4 ZE554KL Bootloader (Guide)


In this guide we will let you how to unlock Asus Zenfone 4 (ZE554KL) bootloader. Like most vendors, Asus has also allowed unlocking their ZenFone bootloader and released special application for the purpose. Also, there is an unofficial method. Both methods are describing in the below guide. You can use any method to unlock the bootloader, but we prefer official method.

As you all know, all Asus ZenFone, including the new Zenfone 4 has shipped with locked bootloader. While this is a reasonable security feature of Android, it is also a problem for anyone who wants to install latest firmware update manually via fastboot, install custom ROMs like LineageOS, get root access, install custom recovery, etc.


If you own a Asus Zenfone 4 (ZE554KL variant) and want development on it, then first you need to unlock its bootloader. Since bootloader is a security feature, the process will factory reset your device, so take a backup before proceeding.

Keep in mind that unlocking the bootloader will void your device warranty. If you have enough reason to unlock your Zenfone 4 bootloader, then read on to know how to do it.

Unlock Bootloader on Asus Zenfone 4 (ZE554KL)

Disclaimer: We at droidguiding won’t be liable for any damage to your device whatsoever. We won’t be held responsible if you brick your device. Reader’s discretion is advised.

Official Method:

1. Download official bootloader unlock tool APK for ZenFone 4 ZE554KL from Asus here to your phone.

2. Enable ‘Unknown Sources’ by going to Settings > Security > Device administrators > Unknown sources.

3. Go to where the unlock tool APK is saved and install it.

4. Agree to the warnings and tap OK. Tap on ‘Press to unlock your device’ button. Your phone will restart and start unlocking the bootloader.

Unofficial Method:

If above method does not work, try the unofficial method. It is complicated and requires ADB and fastboot driver setup on your computer.

1. Download the unlock toolkit from here and unzip it on your PC.

2. Save all files inside the ADB installation directory and open a command window from there.

3. Switch off your phone, press and hold the Volume Up and Power button to enter Fastboot mode.

4. Connect your device to the PC using the USB cable and run the below command:

fastboot devices

5. If you see your device is listed, then double-click on the ‘ze554kl_unlock.bat‘file. If you are using Mac/Linux, then run the command: ./

6. It will start to unlock bootloader on Asus Zenfone 4. Once done, reboot your phone.

If you have any question regarding this guide, leave it in the comment. (Source – XDA)