Why to block the bootloader on Xiaomi smartphones: 5 reasons to return factory security settings

Have you ever wondered why smartphone makers like Xiaomi default to lock a bootloader on their devices? In the pursuit of customization, many users will unlock it to install custom firmware, obtain root rights, or remove embedded applications. But what if we say that more than 60% of the problems with the “bricking” of Xiaomi devices are due to the unlocked bootloader?

This article is not about unlocking a bootloader -- there are hundreds of guides on the Internet -- but here we're going to go through the reverse of why and when to lock it back, the risks of unlocking it, and how to get back the factory protection right, and if you're selling your phone, running into firmware bugs, or just wanting to get your warranty back, that information will save you time and nerves.

1.What is Xiaomi bootloader and why it is blocked by default

A bootloader is a low-level program that runs before the Android operating system boots, which checks the integrity of system files and “decides” whether to allow the OS to run. Manufacturers, including Xiaomi, block the bootloader on all devices for three key reasons:

• 🔒 Malware protection: Without blocking, an attacker could replace firmware with infected ones without even cracking the screen password.
• 📱 Safeguard: Unlocking automatically voids the official warranty (this is stated in the Xiaomi user agreement).
• 🛠️ Stability: Castom firmware often conflicts with “iron”, which leads to overheating, battery discharge or “flights” of the system.

For example, in the Redmi Note 12 Pro models+ and Xiaomi 13 Ultra bootloader integrated with the Secure Boot module, which encrypts critical partitions of memory. Unlocking disables this protection, making the device vulnerable to attacks via fastboot or EDL-regime.

2. Top.-5 Reasons to block the loader back

If you have already unlocked the bootloader, here are the situations when it is worth returning everything as it was:

1. Selling or transferring a phone: An unlocked bootloader allows the new owner to easily bypass Mi Account protection (even if you do a reset) that is a risk to your data and reputation.
2. Problems with OTA-Updates. On devices with unlocked bootloader. MIUI Often refuses to install updates "over the air", citing "signature inconsistency».
3. If, after installing LineageOS, Pixel Experience or other firmware, the phone slows down, overheats or discharges quickly, locking the bootloader and returning to stock MIUI can solve the problem.
4. Banking application requirements: Many banks (e.g. Sberbank or Tinkoff) block access to their applications on devices with an unlocked bootloader due to the risk of data leakage.
5. Restoration of warranty: Some Xiaomi service centers may turn a blind eye to unlocking if you block it before visiting (but it doesn’t always work!).

Important: Locking the bootloader erases all data on the device (including files on internal memory!) This is an integral part of the process - so Xiaomi prevents the ability to recover data after a reset.

💡

Locking the bootloader is the only official way to get back the warranty and protection against malware, but it completely cleans the device.

3. Risks of unlocked bootloader: what awaits you

Many users believe that unlocking the bootloader is a harmless procedure, and in practice, it opens the door to a number of problems:

Especially critical is the situation with Xiaomi models that support Widevine L1 (for example, Xiaomi 14 or POCO F5). Unlocking the bootloader lowers the level of protection to Widevine L3, which causes Netflix, Disney+ and other services to stop playing content in Full HD.

⚠️ Note: If you use your phone to handle sensitive data (e.g., access to corporate mail or other information). CRM), An unlocked bootloader can be a reason to be fired. Many companies check the status of the bootloader through the use of a bootloader. MDM-system.

4. How to check the status of the bootloader on Xiaomi

Before you lock the bootloader, make sure it's actually unlocked. There are two ways to do this:

Method 1: Through fastboot mode

1. Turn off the phone.
2. Press the Power + Volume buttons down until the Fastboot logo appears.
3. Connect the device to the PC and type the command: fastboot oem device-info
4. If the answer is Device unlocked: true, the bootloader is unlocked.

Method 2: Through the MIUI settings

Go to Settings → About Phone → MIUI Version and tap 7 times according to version. Then go back to Settings → Additional → Developer. If there is a “bootloader Status” option** that says Unblocked, confirmation received.

💡

On some models (e.g. Redmi K50), the bootloader status can be checked by using the command adb shell getprop ro.boot.verifiedbootstate.

5. Step-by-step instructions: how to block the bootloader on Xiaomi

The bootloader lock process is officially supported by Xiaomi, but has a number of nuances.

• 🖥️ Computer with drivers installed ADB/Fastboot.
• 🔌 Cable USB Type-C (preferably original).
• 📱 Charge of the phone at least 60%.
• 🔐 Mi Account Linked to the Device.

If everything is ready, follow the instructions:

Download and install Platform Tools from Google|

Backup your important data (blocking erases everything!)|

Disable Find My Device protection in Google | settings

Make sure the phone has a stock firmware MIUI (Custom firmware cannot be blocked!)-->

1. Activate Developer Mode: Go to Settings → About Phone → MIUI Version and tap it 7 times. Then in Settings → Additional → For developers, turn on “Debugging on USB” and “OEM Unlocking”.
2. Turn the phone into fastboot mode: Turn off the device and press Power + Volume down before the screensaver with a rabbit in a hat-eared (Fastboot logo) appears.
3. Connect your phone to your PC and execute the lock command: fastboot oem lock If a warning appears on the phone screen, confirm the action with the Volume Up button.
4. Wait for the reboot: The phone will automatically restart and begin the process of cleaning the data. This can take 5-15 minutes.

⚠️ Note: If you see an error during the lock FAILED (remote: 'Device is critically locked. Cannot lock', which means that the device has an unofficial firmware installed. MIUI Use the Mi Flash Tool and try again.

6.What to do if the phone does not turn on after blocking

In rare cases, locking the bootloader can lead to the "bricking" of the device.

• 🔧 Interrupted locking process (e.g., cable shutdown).
• 📦 Installed custom firmware, incompatible with locking.
• 🔋 Battery discharge below 30% during the procedure.

If the phone doesn’t respond to the power button or is stuck on the MI logo, try the following steps:

Important: If you have blocked the bootloader on a device with a MediaTek processor (such as the Redmi Note 11 or POCO M5), you may need an authorized Mi Authorized Account to restore, which is only available to service centers.

7. Myths and truths about locking up Xiaomi bootloader

There are many myths surrounding the bootloader locking procedure.

Another common misconception is that Xiaomi is blocking the bootloader to force users to buy new phones. In fact, the main reason is Google's requirements: To certify Android devices, manufacturers must protect the bootloader, otherwise the phone will not get access to Google Play services.

Frequently asked questions