Xiaomi Mi 4 Pro (codenamed cancro) is the legendary 2015 smartphone that is still used by enthusiasts thanks to its powerful hardware and active developer community. However, with the release of new versions of Android, official support has long been discontinued, and users face security issues, app compatibility and slow work.
This article will help you understand how to flash the Mi 4 Pro in 2026, from unlocking the bootloader to installing custom firmware like LineageOS or Pixel Experience. We will look at all the current ways – through Fastboot, Recovery (TWRP) and the regular MIUI Updater, and also tell you how to avoid the typical errors leading to a “brick” (turning the phone into a “brick”).
Important: there are always risks involved in the firmware procedure, and even if you follow the instructions, there is a possibility of data loss or damage to the device, and if you are a beginner, carefully study each step and do not miss the warnings.
1. Firmware Preparation: What to Do Before Starting
The Xiaomi Mi 4 Pro firmware requires careful preparation, and without it, you risk getting a broken device or encountering errors like ERROR: bootloader is locked or anti-rollback check fail.
- 📱 Check the device model: go to Settings → About Phone → Model. The Mi 4 Pro (or cancro in the engineering menu) should be listed. The firmware from another model will lead to a blink!
- 🔋 Charge the battery to at least 70 percent, and interruption due to discharge is one of the main causes of failure.
- 💾 Backup: Use Mi Cloud, Google Account, or manual copying on your PC. The firmware erases all data!
- 🖥️ Install drivers: for Windows, download the Mi Flash Tool (includes drivers), for Linux/macOS, adb and fastboot via package managers.
Also prepare:
- 🔗 USB Cable: Original or high quality (cheap cables may interrupt the connection).
- 📁 Firmware files: official (from the Xiaomi Firmware Updater website) or custom (from the XDA Developers forum).
- 🔓 Unlocked bootloader: without this, it is impossible to install custom software. The process takes up to 72 hours (see section 3).
⚠️ Warning: If your Mi 4 Pro is purchased in China, check if the firmware is blocked for international regions. China-based devices ROM may require additional manipulation (e.g., region change via Mi Account).
2. firmware choice: official MIUI vs custom ROM
The choice of firmware depends on the stability of work, the presence of bugs and the availability of features. Let's consider the main options for the Mi 4 Pro:
| Type of firmware | Advantages | Deficiencies | Recommendation |
|---|---|---|---|
| Official MIUI (Stable/Developer) | Maximum compatibility, OTA- Updates, support for all functions (NFC, IR- blaster). | Outdated version of Android (up to 6.0), a lot of bloatware, advertising in system applications. | For those who need stability and no need for Android relevance. |
| LineageOS (14.1–17.1) | Clean Android without Bloatware, regular security updates, support to Android 10. | NFC or IR- blaster may not work, there are no MIUI- chips (for example, design themes). | The best choice for balancing performance and relevance. |
| Pixel Experience | The interface is like Google Pixel, current Android features (up to version 12). | There may be bugs with a camera or sensors, less stability compared to LineageOS. | For fans of stock Android and experiments. |
| Custom MIUIs (such as MIUI Pro) | Modern MIUI design based on the new Android, removed by Bloatware. | Low stability, possible performance problems. | Only for experienced users who are ready for bugs. |
For beginners, we recommend starting with an official stable MIUI (e.g. MIUI 10 based on Android 6.0. If you want a newer version of Android, choose LineageOS 17.1 (Android 10). Before downloading, check compatibility with your model on the forum. XDA.
⚠️ Warning: Firmware for Mi 4 (not Pro) is not suitable for Mi 4 Pro due to different hardware configurations (e.g., another camera module). Make sure the firmware file contains in the name cancro_pro or mi4_pro.
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Before downloading the firmware, check its hash (MD5) with a utility like 7-Zip or HashMyFiles, which will protect against corrupted files that can lead to installation errors.
3. Unlocking the bootloader: step-by-step instructions
The Xiaomi Mi 4 Pro bootloader is locked by default. Without it unlocking, you can't install custom Recovery or firmware. The process takes up to 3 days due to a check by Xiaomi. Here's how to do it:
- Attach Mi Account to your device: Go to Settings → Xiaomi Account and log in. Make sure your account is confirmed via email/phone.
- Activate USB debugging: In Settings → About Phone tap 7 times on MIUI to enable Developer Mode. Then in Settings → Additional → For developers, turn on USB debugging and OEM unlock.
- Download Mi Unlock Tool: The official utility is available on Xiaomi's website. Install it on your PC.
- Connect your phone to your PC: Launch the Mi Unlock Tool, log in to the same account you have on your phone. Follow the instructions.
- Wait for confirmation: Xiaomi sends an SMS/email with the unlock confirmation in 72 hours (sometimes faster).
If the program is unable to unlock or Device is not supported:
- 🔄 Try another one. USB-cable.
- 📱 Restart your phone and PC.
- 🕒 Wait longer — sometimes Xiaomi delays unlocking up to 5 days.
- 🛠️ If the device is purchased in China, you may need to change region through your Mi Account (see instructions at 4PDA).
What if the Mi Unlock Tool can’t see the device?
4. Installation of TWRP Recovery: Why You Need It and How to Do It
TWRP (Team Win Recovery Project) is a custom recovery that allows you to install firmware, backup and restore the system. Without it, custom ROM installation is impossible. For the Mi 4 Pro, TWRP version 3.6.2 or later is suitable.
Installation instructions:
Download the latest version of TWRP for cancro from the official website
Unpack the archive and rename the file to twrp.img
Download ADB & Fastboot Tools (e.g. 15 Seconds ADB Installer)
Connect your phone to your PC in Fastboot mode (turn off, then clamp Volume down) + Nutrition)-->
fastboot flash recovery twrp.img
fastboot boot twrp.imgAfter executing the commands, the phone will automatically restart to TWRP. In the first run, the system will prompt you to allow changes (Swipe to Allow Modifications) - swipe to the right, otherwise you will not be able to flash custom ZIP- files.
⚠️ Warning: If the phone loads into standard recovery after installing TWRP, the official firmware has overwritten it. To avoid this, click disable_forced_encryption.zip immediately after installing TWRP (available on XDA) This will disable the forced encryption that interferes with the custom ROM.
5. Firmware through Fastboot: the official method
The Fastboot method is suitable for installing official MIUI firmware, and it is considered the most reliable, since the firmware is installed directly into the system partition without intermediaries.
- 📁 Firmware file in.tgz format (download from Xiaomi Firmware Updater).
- 🖥️ The Mi Flash Tool (available on the official website).
- 🔌 Cable USB and unlocked loader.
Step-by-step:
- Unpack the firmware archive into a folder without Cyrillic characters (e.g., C:\Mi4Pro\rom).
- Run the Mi Flash Tool on behalf of the administrator.
- Connect the phone in Fastboot mode (turn off, then press Volume Down + Power).
- In the program, click Select and specify the path to the folder with the firmware.
- Select Clean All or Clean All and Lock (if you want to lock the bootloader again).
- Press Flash and wait until it is completed (5-10 minutes).
If the process is successful, the phone will reboot to a new firmware, and if you have an anti-rollback check fail, you are trying to install an older version of MIUI than the one you already have.
- Download a newer firmware.
- Or, run an anti-rollback fix (available on forums like 4PDA).
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Clean all and lock mode will block the bootloader after the firmware is installed. Use it only if you are sure that you will not install custom ROMs in the future.
6. Firmware through TWRP: custom ROM and mods
Installing custom firmware through TWRP gives you more freedom, but it takes care. Mistakes here more often lead to a breeze.
- 🔓 Loader unlocked.
- 📱 Installed TWRP (see section 4).
- 📁 The firmware is downloaded in.zip format and placed on the internal memory or SD- card.
Instructions:
- Boot into TWRP: Turn off the phone, then press Volume Up + Power.
- Backup your current firmware: Backup → Select partitions (Boot, System, Data) → Swipe to Backup.
- Reset: Wipe → Advanced Wipe → Mark Dalvik, Cache, System, Data → Swipe to Wipe.
- Install → Select ZIP- file → Swipe to Confirm Flash.
- If required, go to GApps (for Google services) and Magisk (for root).
- Reboot: Reboot → System.
The first download can take up to 15 minutes - don't interrupt! if the phone is stuck on the logo for longer than 20 minutes:
- 🔄 Reboot to TWRP and re-set.
- 📥 Check the firmware compatibility with your model.
- 🔧 Try flashing the kernel (boot.img) separately.
How to use Magisk to get root rights?
7.Recovery after a blink: what to do if the phone doesn't turn on
Brick: A condition where the device does not respond to buttons or loads only to the logo. The Mi 4 Pro features two types of brick:
- Soft-brick: The phone is powered on but not booted into the system (hangs on the logo or boots into recovery).
- Hard-brick: The device does not respond to buttons, is not detected by the PC (the most difficult case).
Recovery methods:
| Type of brick | Signs. | Decision |
|---|---|---|
| Soft-brick | Logo hover, cyclic reboot, Fastboot/Recovery access. | 1. Sweeve the official firmware through the Mi Flash Tool (Clean All Mode). 2. If it doesn't work, install TWRP and run custom ROM. |
| Hard-brick | No response to buttons, PC doesn't see the device, black screen. | 1. Try to pin down Volume + Power on 30 seconds (sometimes forced reboot helps). 2. Use EDL- Mode (emergency boot mode) with Qualcomm box or Mi Flash Pro utility (requires authorization from Xiaomi). |
| Bootloop (Cyclical Reboot) | The phone is constantly restarting without reaching the system. | 1. Load to TWRP and clear the cache (Wipe → Cache/Dalvik). 2. Refuse the kernel (boot.img) from the official firmware. |
If none of these methods worked, contact the service center. For the Mi 4 Pro, EDL recovery often requires special equipment (such as a UFi Box or EasyJTAG) that only professionals have.
⚠️ Warning: When you recover through EDL, you risk damaging IMEI or modem, causing the network to lose. If you're not sure about your ability, you can trust the repair team.
8. Frequent errors and their solutions
When you run the Xiaomi Mi 4 Pro, users often encounter common bugs, and here are the most common ways to fix them:
- 🚫 ERROR: bootloader is locked Reason: bootloader is locked Reason: bootloader is not unlocked Solution: Unlock it via Mi Unlock Tool (see section 3).
- 🚫 anti-rollback check fail Reason: Attempt to install an older version MIUI Solution: Sweat a newer firmware or patch anti-rollback fix.
- 🚫 This package is for "cancro" devices; this is a "" Reason: Firmware is not suitable for your model. Solution: Download the correct version (for cancro_pro).
- 🚫 E: unknown command [log] in TWRP Reason: Damaged firmware file or incompatible version TWRP Solution: Reinstall TWRP and check the hash amount ZIP- of the file.
- 🚫 Phone doesn't turn on after firmware Reason: Incompatible firmware or interrupted process Solution: Try flashing the official MIUI through Fastboot.
If the error is not listed, look for its code on the 4PDA or XDA forums, often by other users.
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Always check the reviews of a particular version of ROM on the forums before you run your firmware. For example, some LineageOS builds for the Mi 4 Pro have problems with GPS or camera performance.