This wikiHow teaches you how to use Android Debug Bridge (ADB) for Windows to lock down your Android bootloader. Warning: This will likely format your device. Back up all data first!
Part 1 of 2: Installing Android Debug Bridge (ADB)
Step 1. Open a web browser on your computer
This guide assumes a Windows system, but the process may be similar on a Mac
Step 2. Go to
Step 3. Click on ADB Installer v1.4.3
As of August 16, 2017 this is the last version. If you see "Latest Version" next to another version, click that link.
Step #4. Click Download
It's the big green oval button. It will download a.zip file containing the installation file that ends with '.exe' once unpacked.
Step 5. Double click on the downloaded file
This will open the contents of the.zip.
Step 6. Double click on the file in the.zip that ends with '.exe
It should be called something like 'adb-setup-1.4.3.exe'. This will open a command prompt, asking if you want to install ADB and Fastboot.
Step 7. Press Y
Now you will be asked if you want to install ADB for the entire system.
Step 8. Press Y
Now you will see a message about installing device drivers.
Step 9. Press Y
After a few moments, the Device Driver Wizard will appear.
Step 10. Click Next
Step 11. Click on Exit
ADB will now be installed on your computer.
Part 2 of 2: Locking the bootloader
Step 1. Connect your Android to the computer with a USB cable
If you don't have the same USB cable that came with your device, make sure you're using a secure, compatible version.
Depending on your device, you may need to install drivers for your computer to recognize your Android. You can download it from the website of your phone or tablet manufacturer
Step 2. Press ⊞ Win+S
The Windows search bar opens.
Step #3. Type cmd
A list of matching search results will appear, including 'Command Prompt'.
Step 4. Right click on 'Command Prompt' and choose Run as administrator
This step opens an administrator-level Command Prompt window.
Step 5. Click Yes to confirm
The command prompt will open.
Step 6. Type adb reboot bootloader and press ↵ Enter
The ADB program is running.
Step 7. Type fastboot oem lock and press ↵ Enter
The command is executed and the bootloader is locked. If you see an error message, try one of the following commands as an alternative:
- fastboot flashing lock
- oem relock
Step 8. Type fastboot reboot and press ↵ Enter
This will reboot your Android and lock the bootloader.