How to flash Xiaomi Mi Mix 3: official and custom firmware

Why do you want to use Xiaomi Mi Mix 3?

The Xiaomi Mi Mix 3, released in 2018, is still a hot-button device thanks to its powerful hardware: Snapdragon 845 processor, 6-10 GB of RAM and unique front-facing camera slider mechanism. However, over time, even flagship models start to slow down due to outdated software.

In this article you will find three proven methods of firmware: through the standard MIUI Updater, manual installation in Recovery and full Fastboot flashing, we also learn how to unlock the bootloader (without this custom firmware can not be installed), where to download official and informal builds, and what to do if after firmware has stopped turning on. Mi Mix. 3 It has two modifications – global (perseus) and Chinese (perseus_cn), And the stains are not interchangeable!

If you’re a beginner, start with an official update via MIUI Updater, which is the safest method. Power users may consider custom firmware like LineageOS or Pixel Experience, but they require unlocking the bootloader and may be unwarranted (if it’s still valid).

Preparation for firmware: what to do before the start

Regardless of the method chosen, preparation is a critical stage, and neglecting it can lead to a "brick" (complete failure) of the device.

• 🔋 Charge the battery to at least 60%. When you run through Fastboot, the phone should not turn off, this will interrupt the process and can damage system files.
• 📱 Back up all the data. The firmware erases user files (especially when you switch to custom OS). Use Mi Cloud, Google Drive, or local copying on your PC.
• 🖥️ Install drivers for Xiaomi on your computer. Download Mi PC Suite or drivers ADB/Fastboot manually.
• 🔗 Check the model of the device. Go to the settings. → The phone. → Version. MIUI Write down the exact name (for example, MIUI Global 14.0.5 for perseus).

Also prepare a USB Type-C cable (preferably original) and make sure that there is enough free space on your PC (firmware weighs 2-4 GB). If you plan to unlock the bootloader, you will need a Mi-account with a tied phone number - without this, Xiaomi will not allow the procedure.

Method 1: Update via MIUI Updater (without loss of data)

This is the easiest and most secure method to install official updates, it doesn't require unlocking the bootloader and it saves all the user data, but it only works for official firmware from Xiaomi.

Instructions:

1. Open the MIUI Updater app on your phone.
2. Click on the three dots in the top right corner and select Select Service Pack.
3. Specify the path to the downloaded firmware file (.zip format). 3 The file name should start with perseus_ (global version) or perseus_cn_ (Chinese).
4. Confirm the installation and wait for the restart. It'll take 5-15 minutes.

If the update has been stuck on the MI logo for more than 20 minutes, don’t panic – sometimes the system will optimize applications for a long time. But if the screen is out and the phone does not respond, try forcibly restarting it by holding the power button for 10-15 seconds.

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If MIUI Updater no button “Select service pack”, update the app via Google Play or download it APK from the official Xiaomi website.

Method 2: Firmware through Recovery (for official and custom ZIP)

This method is suitable for both official and some custom firmware installations (e.g. Xiaomi.eu). Unlike Fastboot, it does not require a PC connection, but an unlocked bootloader is a must for unofficial builds.

Step-by-step:

1. Download the firmware in.zip format and move it to the root directory of the phone’s internal memory (not in folders!).
2. Turn off Mi Mix 3 and press Volume Up + Power to enter Recovery.
3. In the Recovery menu, select Install (or Install), then specify the downloaded file.
4. Confirm the installation with a swipe (in TWRP) or a Yes button (in stock Recovery).
5. After completion, select Reboot System.

If you have stock Recovery, it may not support custom firmware installation, in which case you first need to flash TWRP (instructions in the next section).

Download firmware (.zip) for your model | Checksum (MD5) of the file | Copying file to the root of memory | Check battery charge (>50%) | Unlock bootloader (for custom firmware)

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Method 3: Full Fastboot Firmware (for experienced)

The Fastboot method is the most reliable method for recovering a dead phone or installing full firmware (including boot, recovery, and other partitions). It requires a PC, a cable, and an unlocked bootloader. Attention: it erases all data!

Algorithm of action:

1. Download Fastboot firmware for Mi Mix 3 from the official Xiaomi website (file with the extension.tgz or.zip).
2. Unpack the archive in a folder on a PC (for example, C:\MiMix3_Fastboot).
3. Turn off the phone and press Volume Down + Power to enter the Fastboot (a hare in a hat-eared hat will appear).
4. Connect the device to your PC and open the command line in the firmware folder. Enter the command: fastboot flash all (for Windows) or./flash_all.sh (for Linux/Mac).
5. Wait for the completion (about 5-10 minutes) and automatic reboot.

If the process is interrupted by an error FAILED (remote:'Partition not found'), check that you downloaded the firmware for your modification (perseus or perseus_cn). Also make sure that there are no Chinese characters in the firmware folder on the way – this can cause crashes.

Unlocking the bootloader: a mandatory step for custom firmware

Xiaomi blocks the bootloader on all its devices, including the Mi Mix 3.This means that without official unlocking, you won't be able to install TWRP, LineageOS or other unofficial firmware.The process takes up to 72 hours (due to Xiaomi's validation) and requires a tied Mi-account.

Instructions for unlocking:

1. Link Mi-account to your phone: go to Settings → Xiaomi Account and log in.
2. Activate OEM Unlock and USB Debugging in Settings → Additional → For Developers.
3. Download the Mi Unlock Tool and run it on behalf of the administrator.
4. Log in to the same Mi-account as you did on your phone and connect the Mi Mix 3 in Fastboot mode.
5. Press Unlock and wait for confirmation (it may take several attempts).

⚠️ Note: Once the bootloader is unlocked, all data will be reset and the warranty (if it is still valid) will be canceled.

If the Mi Unlock Tool is running a "Couldn't unlock" error, try it.

• 🔄 Reconnect the phone to another USB-port (preferably) USB 2.0).
• 📱 Restart your phone and PC.
• ⏳ Wait 24-72 hours (sometimes Xiaomi blocks unlocking due to frequent attempts).

Selection of firmware: official vs custom

Before you run the firmware, decide which version of the software you want to install. Each version has pros and cons:

For most users, the best choice is Xiaomi.eu. This firmware removes ads and unnecessary apps, but retains all the features of MIUI. If you want a pure Android, pay attention to the Pixel Experience, but be prepared for possible problems with hardware (for example, a camera slider).

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There is no perfect custom firmware for the Mi Mix 3, all of which have trade-offs. Check reviews on XDA or thematic chats before installing.

Solving problems after firmware

Even with the right firmware, there can be problems, and here are the most common ways to fix them:

• 🔄 The phone is stuck on the logo MI: Try to go to Recovery (Loudness Up). + Power) and make Wipe Data. If it doesn't work, go back to the Fastboot.
• 🔋 Fast battery discharge: After firmware, calibrate the battery: fully discharge the phone, then charge to 100% without interruptions. Repeat 2-3 times.

⚠️ Warning: If after flashing through Fastboot, the phone stopped turning on and didn't respond to buttons, don't panic.Plug it into charging for 30 minutes, then try pinching Volume Down + Eating 20 to 30 seconds, 80 percent of the time, it helps you get out of the soft breech».

If none of the methods worked, contact the Mi Mix 3 owners Telegram chat, which often helps with rare bugs. Also save the error log (if the phone turns on at all), this will speed up the diagnosis.

FAQ: Frequent questions about the Xiaomi Mi Mix firmware 3