The Fastboot tool is one easy way to unlock the Android bootloader.
What to Know
This article explains how to unlock the bootloader on an Android phone.
Some phones require an additional unlock code from the manufacturer to unlock the bootloader.

Open theSettingsapp on your gear.
Near the bottom of the screen, you see theBuild number.
Tap it seven times to initiate the developer options.

You may be prompted to type your password to continue.
Go back and chooseSystemin the configs app.
Locate and selectDeveloper options.

Developer options are likely in the Advanced section.
Tap the down arrow to open those options.
Find theOEM unlockingoption, and toggle the switch on.

Scroll down and locateUSB debugging.
Toggle the switch on.
How to Install Android Tools
Enabling OEM unlocking only makes itpossibleto unlock the machine.

for actually unlock it, youre going to need a couple of Android developer tools from Google.
These are freely available, and theyre simple to use.
Windows
Download the latest Android tools ZIP for Windows.
Unpack the ZIP file into a convenient folder.
Right-hit the folder containing the extracted files.
When the menu pops up, selectOpencommand window here.
Ubuntu/Debian Linux
Open a terminal window.
Use sudo to get root privileges, and use the following command to plant the Android tools.
In the terminal (or Command Prompt), fire off the following command to connect your phone.
Youll see a message requesting access on your phone.
Check the box to always allow the connection, and confirm.
fire off the following command to reboot your phone into the bootloader.
Wait for your phone to reboot.
Youre now ready to unlock with Fastboot.
You may be asked to confirm.
Your bootloader is unlocked, and youre ready to continue on toflashing custom recoveryandrootingyour gadget.