Blocking the bootloader on Xiaomi Redmi Note 8 Pro: how to do it without losing data

The bootloader on Xiaomi smartphones is a software component that controls the process of launching the operating system. On the Redmi Note 8 Pro, it is blocked by the manufacturer by default, but many users will unlock it to install custom firmware, obtain root rights or test beta versions of MIUI. However, after experiments, it often becomes necessary to return everything “as it was” – for example, for warranty repairs, sale of the device or fixing errors in the system.

The main problem with blocking a bootloader is the risk of data loss. Standard methods through the Mi Unlock Tool or fastboot usually require a complete hard reset, which leads to the removal of photos, contacts and applications. In this article, we will discuss ways to lock the bootloader on the Redmi Note 8 Pro without losing data, including official and alternative methods, and also elaborate on the nuances of the procedure for this particular model.

Why a lockdown of a loader may be necessary

The unlocked bootloader gives the user advanced features, but has disadvantages:

• 🔓 Security: The device becomes more vulnerable to malware as an attacker can install their firmware.
• 📱 Guarantee: Most Xiaomi service centers refuse repairs under warranty if the bootloader is unlocked.
• 🔄 Stability: Custom firmware or incorrect partition manipulation can lead to failures that are difficult to eliminate without blocking the bootloader.
• 💰 Sale: When transferring a phone to a new owner, an unlocked bootloader can cause suspicions of the device's "curvature.

On the Redmi Note 8 Pro (codenamed begonia), the bootloader lock is complicated by the fact that the model belongs to the Note series with a Mediatek Helio G90T processor, rather than the Qualcomm Snapdragon, as many other Xiaomi smartphones do.This imposes restrictions on the available tools and commands fastboot.

⚠️ Note: If you have previously installed informal firmware (such as LineageOS or Pixel Experience), locking the bootloader may cause the device to blink. MIUI for your region.

Preparation of the device before blocking the loader

To minimize the risk of data loss, several mandatory steps must be taken:

1. Back up via Settings → Additional → Backup and Reset. Use Mi Cloud or local storage. Please note that some data (such as Wi-Fi passwords or some application settings) may not be saved.
2. Check out the MIUI version. bootloader lock is only possible on official firmware. Go to Settings → About the phone and compare the version with the latest stable builds on the Miui Download website.
3. Make sure you have a Mi Account linked to your device. Without it, the Mi Unlock Tool will not allow you to lock.
4. Charge the battery to at least 60%, interruption of the process due to discharge can lead to software damage.

For Redmi Note 8 Pro, it is critical to use the correct firmware version. For example, if you installed Global ROM and your phone was originally on China ROM, locking the bootloader may result in an error. Check the firmware region in Settings → About Phone → MIUI version (CN, EU, IN, RU, etc.).

The official method: use of Mi Unlock Tool

Mi Unlock Tool is the official Xiaomi utility designed to unlock and lock the bootloader, but in the latest versions of the program, the lock function is hidden and requires additional manipulation.

1. Download the latest version of the Mi Unlock Tool from the official en.miui.com/unlock website (use the Windows version).
2. Install drivers for the Redmi Note 8 Pro via Mi PC Suite or manually (download on Xiaomi website).
3. Activate Fastboot mode: Turn off the phone. Press Volume down + Power before the Fastboot logo appears.
4. Connect your phone to your PC and launch the Mi Unlock Tool. Sign in with the same Mi Account as your phone.
5. Press Unlock (yes, this button is the same process that locks). The utility will check the status of the bootloader and prompt to block it if it is already unlocked.
6. Confirm the action. It takes 10 to 15 seconds. When it's done, the phone automatically restarts.

Important: If the Mi Unlock Tool is a Couldn’t unlock or Device not supported error, it may mean that:

• 🔌 There is an unofficial firmware on the phone.
• 🔄 Mi Account is not tied to the device (requires 72 hours of waiting after the link).
• 📱 The device is blacklisted by Xiaomi (for example, after multiple unlocks).

⚠️ Note: If the bootloader locks the phone into Fastboot mode or gives an Anti-rollback error, this means that the firmware version is incompatible with the current bootloader version.

Alternative method: blocking through Fastboot commands

If the Mi Unlock Tool doesn’t work, you can try locking the bootloader through fastboot commands, a method that requires a strong command line command and is only suitable for advanced users.

You'll need:

• 🖥️ Computer with installed ADB Fastboot (you can download it as part of Android) SDK Platform-Tools).
• 📱 Phone in Fastboot mode (how to translate - see previous section).
• 🔑 Antirollback.db file for your model (can be extracted from official firmware).

Instructions:

1. Connect the phone to your PC and check for detection by the command: fastboot devices must display the serial number of the device.
2. Unlock the critical area (only if the bootloader is already unlocked): fastboot oem unlock-go
3. Lock the bootloader with the command: fastboot oem lock On the Redmi Note 8 Pro, this command may not work due to Mediatek restrictions. In this case, use an alternative command: fastboot flashing lock
4. Reboot the device: fastboot reboot

If the phone does not boot after the instructions are executed, this means that the firmware is incompatible with the locked bootloader.

1. Download the full firmware package for your model from the Xiaomi Firmware Updater website.
2. Sweep your phone through the Mi Flash Tool with the clean all and lock option (this will result in data loss!).

💡

Before using fastboot commands, check the bootloader version with fastboot getvar anti. If the anti value is 3 or higher, the lock may result in an error due to the anti-rollback policy.

Comparison of loader locking methods

To choose the best method, compare the official and alternative methods on key parameters:

For most Redmi Note 8 Pro users, the Mi Unlock Tool is the best solution, as it takes into account the features of the Mediatek processor and minimizes risks. However, if the utility refuses to work, alternative methods through fastboot may be the only way out - but only if you are ready for potential data loss.

💡

On the Redmi Note 8 Pro, locking the bootloader through fastboot commands often ends in an error due to the limitations of the Mediatek processor. Use this method only if the Mi Unlock Tool does not work.

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

If after blocking the Redmi Note 8 Pro bootloader, it stopped booting (hang on the MI logo or left for Fastboot), this means that:

• 🔄 Firmware is incompatible with a blocked bootloader (anti-rollback is violated).
• 📱 In the boot or recovery sections, traces of custom firmware remained.
• 🔋 There was a failure when writing data to the misc section.

Decisions:

1. Flush the official firmware through the Mi Flash Tool: Download the official firmware for your model (choose Fastboot ROM). Unpack the archive and launch the Mi Flash Tool. Connect your phone in Fastboot mode and select the clean all and lock option. Press Flash and wait for completion (10-15 minutes).
2. Use it. EDL-Mode (power users only): If the Mi Flash Tool doesn't help, you can flash your phone in Emergency Download Mode (EDL) using Qualcomm QDLoader or Mediatek SP Flash Tool. This method requires a special cable or testpoints on the board.

⚠️ Attention: Firmware through EDL It can lead to hard-brick if you use the wrong firmware version or interrupt the process. On the Redmi Note 8 Pro, this method is recommended only in extreme cases.

How to avoid data loss when blocking the bootloader

While there is no complete guarantee of data retention, the following steps will help to minimize the risks:

1. Use TWRP for backup: If you have a custom TWRP backup installed on your phone, make a full /data backup before locking. To do this, adb backup --twrp --system --data --boot Save backup to your PC or external drive.
2. Check firmware compatibility: Make sure the MIUI version matches your device’s region. For example, if the phone was originally on China ROM and you installed Global ROM, locking the bootloader may end up in error.
3. Disable OEM Unlock in Settings: Before blocking, go to Settings → For Developers and turn off the OEM Unlock option. This will reduce the risk of conflicts.
4. Use the Mi Flash Tool with the save user data option: When you are running through the Mi Flash Tool, select the clean all option (no lock), and then manually lock the bootloader through fastboot.

On the Redmi Note 8 Pro, it is especially important to monitor the anti-rollback version (you can check the fastboot getvar anti command). If the value is higher than 3, locking the bootloader without resetting data is almost impossible - you will need a complete firmware reflash.

FAQ: Frequent questions about locking the bootloader on the Redmi Note 8 Pro