Android Marshmallow for Asus ZenFones
How to unofficially unlock ASUS Zenfone 2 bootloader ASUS

ASUS Zenfone 2 users are in for some great news, as the industrious XDA senior member, ravian29, has just posted a tutorial for unlocking the bootloader on the phone, with due credit to the contributions of other XDA members, shakalaca and fuzzybuffalo.

As this is an unofficial bootloader unlock tool, ASUS will not offer any technical help or support for issues arising after unlocking the phone's bootloader.

IBTimes UK reminds readers that it will not be held liable for any damage to device during or after unlocking the phone's bootloader. Users are advised to proceed at their own risk.


  • Ensure that your Zenfone 2 is rooted on the latest stock firmware (v2.19.40).
  • ADB must be installed and fully functional on your computer.
  • Download black splash screen to your computer.

Steps to unofficially unlock ASUS Zenfone 2 bootloader

Step 1: Connect your ASUS Zenfone 2 to the PC via USB cable.

Step 2: Launch the ADB command window on computer and enter the following commands:

  • adb shell (hit enter)
  • su (hit enter)
  • getprop ro.isn > /factory/asuskey (press enter)
  • reboot bootloader (hit enter)

Step 3:At this moment, the phone will reboot in recovery mode, and the phone will update itself and restart once again. Now, the ASUS splash screen will be white, which indicates the factory lock has been removed.

Step 4: Navigate to the adb folder and open cmd and then type the following commands:

  • adb reboot bootloader (press enter)
  • fastboot devices (press enter)

Step 5:See if device is listed and enter the following:

fastboot flash splashscreen splashscreen.img (press enter)

Step 6: Restart your phone and now black splash screen is back. Your bootloader is now unlocked.

You can follow another method (below) to unlock the bootloader if the above method did not work for you:

Ensure that you have installed all ADT packages from this link:

1. Download Modaco Superboot file for Asus Zenfone 2 Ze551ml from this link:, and save them to your computer.

2. Once downloaded, extract it by right clicking and extract all.

3. On your device, click on Settings > Developer Options > Turn USB Debugging On.

4. Plug the device in to your computer via USB cable.

5. Open the superboot folder that we just extracted (until you see the folder with fastboot-windows inside it), then hold the shift key down on your computer and right click any blank area.

6. Now, select open command window here.

7. In the command prompt, type the following and hit enter at the end of each line.

  • adb-windows reboot bootloader (and wait for the device to reboot)
  • fastboot-windows oem unlock (If it gets stuck at waiting for device here, download and install PDANet on your computer, once installed, unplug then plug the device back in and see if that fixes it)

8. Once it runs, the device should display a screen asking you if you are sure. Click yes using the volume buttons. The device will go back to the bootloader screen but say unlocked at the bottom.

[Source: XDA and Unlock Bootloader]