Unlock your ZTE Nubia Red Devil

OS: Android 8.1 Oreo

CPU: Octa-core (Quad Core 2.45GHz Kryo, Quad Core 1.90GHz Kryo) CPU Clock

RAM: 6GB/8GB

Display: 6.0 inches FHD

Camera: 24 Megapixels

Battery: 3,800 mAh Lithium-Polymer battery

1. Use the Tenorshare 4uKey for Android app.
2. Make a hard reset (factory reset).
3. How to use a low battery to unlock a phone locked with a graphic key.
4. Delete 'gesture.key' and 'password.key' using Aroma File Manager.
5. Restore access to your smartphone using your Google Account.

1. Use the Tenorshare 4uKey for Android app.

Connect your phone to PC with USB cable and launch Tenorshare 4uKey for Android.
In the menu that appears on the PC screen, click Remove.
After verifying the data, the removal of the smartphone screen lock will begin. The program will warn you about deleting all data on the phone, to continue working, click OK.
After the process of removing the lock is completed, put the phone into recovery mode according to the prompts on the computer screen.
Click the Next button, then follow the steps recommended by the program to restore the device to factory settings and reboot it. After rebooting the smartphone, the screen lock will be disabled.

2. Make a hard reset (factory reset)

To get started, turn off your smartphone.Simultaneously press and hold for about 10-15 seconds one of the button combinations:
Volume down button + Power button;
Volume up button + Power button;
Volume down button + Power button + Home button;
Volume down button + Volume up button + Power button.
Using the volume up/down buttons to navigate through the menu options, select Recovery and press the power button.
Using the volume buttons to navigate through the menu, select Wipe data/factory reset. and press the power button
Confirm the hard reset operation.

3. How to use a low battery to unlock a phone locked with a graphic key.

You need to wait until the battery of the phone is discharged.
When the battery has a few percent left, the phone will report this and open the menu with power settings, that is, it will unlock the phone.
You need to open the security settings and disable the lock.

4. Delete 'gesture.key' and 'password.key' using Aroma File Manager.

You need to turn off the phone and prepare a memory card.
Transfer the Aroma File Manager program using a computer to the phone's memory card. Insert the memory card back into the phone.
Put your smartphone into recovery mode using the button combinations that are suitable for your particular model.
In recovery mode, follow the path Install zip -> Install zip from sdcard -> Choose zip from sdcard, go to the archive folder with this program and select it.
After starting the program, you will need to go to the folder /data/system and delete the files 'gesture.key' and 'password.key' (for Android 4.4 or lower) or 'getekeeper.password.key' and 'getekeeper.pattern.key' (for Android 5 or higher)
Reboot your smartphone.

5. Restore access to your smartphone using your Google Account.

When you try to unlock the phone several times, Forgot password? will appear on the screen. Click on it.
Choose the option - recovery with a Google account. You will need to enter your Google Account username and password.
Remove the screen lock from the settings.

Thomas Nilan
Smartphone Expert

Thomas Nilan is a mobile phone expert with in-depth knowledge of the Android and iOS operating systems, who understands the settings of various hidden features that allow you to expand the capabilities of your smartphone, as well as get information about what is going on inside the phone for future repairs. He is an authority in his field, which has allowed him to become a ghostwriter for several technology publications, and he enjoys writing small mobile applications for testing smartphones.