How to upgrade Xiaomi Mi Mix 3 to the current version of MIUI: all ways

The Xiaomi Mi Mix 3, released in 2018, is still a popular smartphone thanks to its frameless design, slider camera and powerful hardware. However, with the release of new versions of MIUI and Android, device owners are faced with the question: how to update the firmware to avoid losing functionality and turning the phone into a “brick”?

In this article, we will discuss all the current ways to update the Mi Mix 3 (codenamed perseus), including official methods through Settings and Mi Flash Tool, as well as alternative options for power users. We will pay special attention to the risks when updating to informal firmware and the nuances of working with an unlocked bootloader. OTA-updates or you want to go to custom firmware - here you will find step-by-step instructions taking into account all the "pitfalls».

1.Preparation for the update: what to do before the start

Before you start updating, it is critical to follow several preparatory steps, neglecting them can lead to data loss, malfunctions, or even a device blink.

First, check the current version of MIUI and Android on your Mi Mix 3. To do this, go to Settings → About Phone. The latest official version for this model is MIUI 12.5 based on Android 10 (for global firmware). If your version is older, the update is only possible through manual firmware.

📱 Save Data: Use Mi Cloud, Google Drive, or Local Backup via Settings → Additionally. → Backup and reset.
🔋 Battery charging: charge level should be at least 60%.When upgrading via Fastboot, it is recommended to connect the device to a power source.
🌐 Stable Internet connection: it is better to use Wi-Fi, not mobile Internet, to download firmware weighing 1.5-2.5 GB.
🔐 Unlock the bootloader (if necessary): if you plan to install custom firmware, unlock Bootloader in advance through the official Xiaomi tool.

📊 How often do you update your firmware on Xiaomi?

Every time you go out, OTA.

Six months

Only with critical bugs.

Never update.

⚠️ Note: If your Mi Mix 3 is purchased in China (the domestic version), installing a global firmware may result in a network lock due to differences in modules. NFR Modem. Before updating, specify the model in Settings → The phone. → Version. MIUI (Global has the suffix Global).

Method 1: Air Update (OTA)

The easiest and safest method is to upgrade via OTA (Over-The-Air), which is suitable if your Mi Mix 3 is already running on the official firmware and receives notifications about new versions, the process takes 10-30 minutes and does not require a connection to a PC.

To check for updates:

Open the Settings. → The phone.
Slip on the item System Update.
Click Check for updates.
If the update is available, download it and confirm the installation.

If OTA-No update is available, there are possible reasons:

🚫 The device is on custom firmware (for example, LineageOS or Pixel Experience).
🌍 The firmware region does not match your location (for example, Chinese firmware on your device in Russia).
🔄 Xiaomi servers are temporarily unavailable (check status on Downdetector).

Backup data | Connect to Wi-Fi | Charge battery to 60%+|Close all background applications-->

⚠️ Attention: If after OTA-Mi Mix 3 has started to overheat or discharge quickly, perform a factory reset via Settings → Additionally. → Backup and reset → Resetting. This is due to conflicts between old and new system files.

Method 2: Manual installation of firmware through Recovery

If OTA-Update is not available, but you want to stay on the official firmware, you can install it manually through Recovery Mode. This method is suitable for firmware with the.zip extension and does not require unlocking the bootloader.

Instructions:

Download the official firmware for Mi Mix 3 (perseus) from Xiaomi Firmware. Choose the version that is relevant to your region (e.g, miui_MIMIX3Global_V12.5.1.0.QEEMIXM_...).
Rename the file to update.zip and move it to the root folder of the phone’s internal memory.
Turn off the device and press the Volume up + Power combination to enter Recovery Mode.
Select Install update.zip to System (manage by volume and power buttons).
Confirm the installation and wait for the process to be completed (about 5-10 minutes).

Type of firmware	Download link	Android version	Notes
Globally stable	Download	Android 10	The latest official version for the Mi Mix 3
China's stable	Download	Android 10	No Google services, only for Chinese models
EEA (Europe)	Download	Android 10	Pre-installed European services

What if Recovery doesn’t see update.zip?

If the update.zip file does not appear in the Recovery menu, check: 1. File name correctness (register is important!). 2. Location - the file should be in the root folder, not in subdirectories like Download. 3. Archive integrity (redownload the firmware and check the checksum MD5). 4. Recovery type: on custom recoveries (for example, TWRP) choose Install instead of Install update.zip.

4. Method 3: Fastboot Firmware (for power users)

The method through Fastboot is suitable for installing official firmware with a complete data reset or recovering the device after a failure. You will need a computer with Xiaomi drivers installed and the Mi Flash Tool utility.

Step-by-step:

Download Fastboot Firmware for Mi Mix 3 from the official website (file with the extension.tgz or.zip). Unpack the archive in a folder on the disk. C:\ (for example, C:\miui_fastboot).
Install Xiaomi and Mi Flash Tool drivers.
Turn off the phone and put it into Fastboot mode, clamping Volume down + Power.
Connect the device to the PC through the original USB-cable.
Launch the Mi Flash Tool, press Select and specify the path to the firmware folder.
Select firmware mode: Clean all - complete data cleanup (recommended when changing the version of MIUI); Clean all and lock - cleaning + lock the bootloader (only for official firmware!); Save user data - saving user data (risk of conflicts).

Flash

💡

If the Mi Flash Tool gives an error critical partition flashing is not allowed, it means that the bootloader is locked. Unlock it through the Mi Unlock Tool and try again.

⚠️ Attention: Fastboot firmware with Clean all and lock will block the bootloader, making it impossible to install custom firmware in the future. TWRP Or Magisk, choose Clean All without locking.

5. Method 4: Install custom firmware (TWRP + Magisk)

For users who lack the functionality of the official MIUI, custom firmware like LineageOS, Pixel Experience or Havoc OS will be an alternative. However, this method requires an unlocked bootloader and installing TWRP Recovery.

Main steps:

Unlock the bootloader via the Mi Unlock Tool (the process takes up to 72 hours to wait for confirmation from Xiaomi).
Install. TWRP Recovery for Mi Mix 3 The following is a quickboot flash recovery twrp-3.7.0_9-0-perseus.img fastboot boot twrp-3.7.0_9-0-perseus.img
Download custom firmware (like LineageOS 18.1 for perseus) and GApps (if you need Google services).
In TWRP, run Wipe → Advanced Wipe and mark Dalvik, Cache, System, Data.
Install firmware and GApps via Install, then restart.

How to roll back an update if the new version of MIUI is not stable?

To roll back to the previous version: Download the desired firmware from the official website. Install it through Fastboot with the Clean all option (data will be deleted!). TWRP, If you have a custom Recovery. ⚠️ A rollback to an older version of Android (like 10 to 9) can lead to problems with Bootloop (getting stuck on downloading).

Do I need to unlock the bootloader to install the official firmware?

No, you don't need to unlock the official firmware via Recovery or Fastboot (with the Clean all and lock option), but if you want to install custom firmware or TWRP, the bootloader must be unlocked.

Where to find the old firmware versions for Xiaomi Mi Mix 3?

The official firmware archives are available on the sites: Xiaomi Firmware (latest versions), Xiaomi Firmware Updater (archive of old builds), 4PDA (Russified and modified firmware). When downloading, check checksums (MD5) to avoid corrupted files.