Unlocking the bootloader is a fundamental step for any enthusiast who wants to take full control of their device based on Android. The procedure opens the door to installing custom recovery, obtaining root access and flashing unofficial operating systems. However, this process is not trivial and requires the user to have a clear understanding of the security architecture of modern mobile platforms.
Before taking active steps, it is necessary to realize that factory unlocking irreversibly changes the security state of the phone. Manufacturers deliberately block the bootloader to prevent the installation of malware and protect the owner's personal data from unauthorized access. Removing this protection puts the device into a mode where the user takes full responsibility for the integrity of the system.
In this article we will analyze in detail the preparation process, the necessary tools and a step-by-step algorithm of actions for different manufacturers. You will learn how to prepare your computer, what drivers to install and what commands to enter into the terminal.
Preparing the device and computer for unlocking
The start of any technical intervention requires careful preparation of the workplace. You will need a computer running Windows, macOS or Linux with ADB and Fastboot drivers installed. Without this toolkit, interaction with the device bootloader is impossible. Download Android SDK Platform Tools from the official website of the developers and unpack the archive into a convenient directory.
A critically important step is to create a full backup copy of the data. The process of unlocking the bootloader almost always initiates a full reset of the device to factory settings (Factory Reset). This means that all photos, contacts, messages and installed applications will be permanently deleted from the internal memory.
⚠️ Attention: The unlocking procedure automatically deletes all user data. Make sure that you have saved important files in cloud storage or on external storage before starting work.
You also need to activate developer mode on the smartphone itself. To do this, go to settings, find the “About phone” section and quickly tap on the build number seven times. After a notification appears that you have become a developer, a new item “For Developers” will appear in the settings menu.
☑️ Preparing for unlocking
Activate OEM unlocking in settings
After enabling developer mode, you need to find the parameter responsible for permission to unlock the bootloader. In the “For Developers” menu, look for the item OEM unlocking (or OEM Unlocking). Move the switch to the active position. The system may ask you to confirm the action or enter the lock screen PIN code.
If you do not see this item in the menu, there may be several reasons. Firstly, some telecom operators or regional firmware versions programmatically hide this option. Secondly, on devices with processors MediaTek or older models Samsung the unlocking mechanism may differ from the standard Fastboot protocol.
Sometimes the “OEM unlock” item remains inactive (gray). This often happens if the device has recently been reset or updated. The security system takes time (usually 7 days or more) to verify the status of the Google account and that the device has not been stolen. In this case, you just need to use the phone as normal without performing a reset until the option becomes available.
If the OEM unlock option is inactive, try connecting to a Wi-Fi network and leaving the phone turned on and unlocked on the screen for several days. This can speed up the status check by the manufacturer's server.
Entering Fastboot mode and connecting to a PC
When the software preparation is completed, you need to put the smartphone into a special bootloader mode. For most devices, the standard mode is Fastboot (or Bootloader Mode). The login method depends on the manufacturer: usually it is a combination of the volume down keys and the power button when the device is turned off.
Connect your phone to the computer using a quality USB cable. It is advisable to use an original cable or a certified analogue, since cheap cables often only support charging and do not transmit data. Open a command line or terminal in the folder with ADB utilities.
Check the connection by entering the command:
fastboot devicesIf you see the serial number of your device in response, it means that the drivers are installed correctly and the smartphone is ready to receive commands. If the list is empty, try reconnecting the cable or reinstalling the drivers.
| Manufacturer | Button combination | Features |
|---|---|---|
| Google Pixel | Volume (-) + Power | Standard Fastboot |
| Xiaomi / Redmi | Volume (-) + Power | Mi account binding required |
| OnePlus | Volume (+) and (-) + USB connection | The mode is called Fastboot |
| Motorola | Volume (-) + Power | Unlock code required |
Unlocking process via command line
The unlocking moment itself is performed by one command, but the consequences of this action significant. Enter the following instruction in the terminal:
fastboot flashing unlockFor some older devices, the command may be different: fastboot oem unlock. After entering the command, a warning about data loss and changes in security status will appear on the smartphone screen. To confirm, use the volume buttons to navigate and the power button to select “Unlock the bootloader.”
The process takes a few seconds. After successful completion, the device will automatically reboot. The first startup after unlocking may take longer than usual as the system checks the integrity of partitions and sets up a new security environment.
⚠️ Attention: After unlocking the bootloader, security features such as Samsung Knox or Google Pay (in some regions) may stop working permanently due to hardware fuses tripping.
Make sure the device battery has at least a full charge 50-60%. Interrupting the unlocking process due to a low battery can lead to the device becoming bricked, when the phone will no longer turn on and will require complex restoration through a service center.
What is the "Device State
Unlocked" status?: This status is displayed when the phone boots and means that the bootloader is unlocked. It warns that the device may be compromised, and is displayed every time you turn it on until the bootloader is locked back.
Unlocking features for different brands
The Android ecosystem is extremely heterogeneous, and each major manufacturer implements its own restrictions. For example, devices Huawei and Honor several years ago completely closed the possibility of obtaining unlock codes for ordinary users, making the procedure inaccessible without special equipment.
Smartphones Samsung have specific protection Knox. The first time you try to unlock the bootloader, a physical fuse (e-fuse) is triggered, which irreversibly changes its state. This permanently disables the ability to use Secure Folders, Samsung Pay, and some banking apps, even if you subsequently lock the bootloader back.
For devices Xiaomi there is a mandatory wait. After submitting an application for unlocking in the utility Mi Unlock Tool you must wait from 7 to 168 hours (depending on account activity and region). Attempts to bypass this wait using third-party services often lead to blocking of the Mi account.
Phone owners Pixel i OnePlus are luckier: for these manufacturers the process is as simplified as possible and does not require long waits or complex registrations, unless the device was purchased from a telecom operator with a locked bootloader.
Unlocking conditions are radically different for different brands: from complete freedom of action to the impossibility of obtaining a code without official permission.
Return to factory state and re-locking
If you decide to return the device to its original state, for example, to sell or fix security problems, the bootloader can be blocked back. To do this, enter Fastboot mode again and run the command:
fastboot flashing lockIt is important to understand that before blocking the device must have stock (official) firmware. An attempt to lock the bootloader when there is a custom recovery or a modified system image will result in the phone being unable to boot.
After locking, the device will reset the data again. The security status will return to “Locked”, but traces of tampering may remain in the logs or at the level of hardware flags (as is the case with Knox). Banking applications may require additional configuration or even refuse to work if the system detects traces of a previous unlock.
Is it possible to unlock the bootloader without losing data?
In the standard scenario, no. Android security protocol requires the user data partition to be cleared when bootloader status changes, so that new owners or malware cannot access the previous owner's encrypted data. There are complex methods for backing up and restoring the userdata partition, but they require advanced skills and do not guarantee success.
Does unlocking affect the operation of the camera?
On many modern smartphones, photo and video processing algorithms are closely related to the integrity of the system. With an unlocked bootloader, some camera applications may not work correctly, and the quality of shooting in third-party applications (for example, Google Camera on non-Pixel devices) may deteriorate due to API restrictions.
What to do if the fastboot command does not work?
Check the installed drivers in Device Manager. Make sure the cable is working properly. Try using a different USB port, preferably USB 2.0, as some older Fastboot implementations do not work correctly with USB 3.0/3.1 ports. Also check to see if the bootloader is hardware locked by your carrier.
Does unlocking void your warranty?
In most regions, unlocking the bootloader will officially void the manufacturer's warranty on the software. In the event of a hardware failure, the service center may refuse free repair, citing software interference. However, consumer protection laws in some countries may allow you to request repairs if the breakdown is not related to user actions.
Can the system be updated over the air (OTA) with an unlocked bootloader?
Usually yes, but with reservations. Official updates may arrive, but the installation process is often interrupted if the system detects modified partitions. In some cases, the update may automatically reload the bootloader or require manual installation confirmation, which is inconvenient for the average user.