The Xiaomi Mi MIX 3 (codename perseus) is a true icon of smartphone innovation from late 2018. It represented the pinnacle of the experimental MIX series, offering a stunning, truly all-screen experience thanks to its satisfying and tactile magnetic slider mechanism. Paired with a flagship Snapdragon 845 processor and a premium ceramic back, the Mi MIX 3 was a bold statement and remains a beloved collector's item in 2025.
However, its official software support ended with a familiar story: the Chinese variant received a final, polished MIUI 12.5 update, while the Global version was left on the earlier, less stable MIUI 12.0. For enthusiasts who want to keep this unique slider flagship in pristine working order, this guide provides the path to restore it, and more importantly, to upgrade it to the best software it ever had.
This is the definitive guide for the legendary Mi MIX 3:
Why You Might Need to Flash Your Mi MIX 3
For a design classic like this, flashing is about preservation and optimization.
Quick Device Overview (Codename: perseus)
Required Tools & Downloads
Download the official firmware for your region for restoration, and the necessary tools to upgrade.
Flashing Methods
Method 1: Flashing Official MIUI 12.0 Stock ROM (Fastboot Mode)
This is the standard method for unbricking your device or restoring it to its final, official global state.
➡ Your phone will reboot into a clean, official MIUI 12.0 system.
Method 2: Upgrading to MIUI 12.5 (via Xiaomi.eu ROM)
This is the recommended path for enthusiasts who want the best possible MIUI experience on their Mi MIX 3.
➡ Your Mi MIX 3 will now run the most refined version of MIUI it ever received, free of bloatware.
FAQs
Q1: Will flashing fix the slider mechanism if it feels stuck?
No. Flashing is a software process. It can fix bugs where the slider doesn't trigger a software action (like opening the camera), but it cannot fix a physical hardware problem like a jammed or broken slider mechanism.
Q2: Can I get MIUI 12.5 on my Global Mi MIX 3 officially?
No. Support for the global version ended at MIUI 12.0. The only way to get the features and optimizations of MIUI 12.5 is to install a custom ROM like Xiaomi.eu, which is based on the final China firmware.
Q3: Is the Mi MIX 3 still a good phone in 2025?
As a daily driver, it's for enthusiasts who appreciate its unique design. The Snapdragon 845 is still powerful, but the slider adds mechanical complexity. It's a fantastic collector's item and a conversation starter that still runs modern apps well after a clean flash.
Q4: Is it safe to re-lock the bootloader?
It is only safe to re-lock the bootloader if you are returning to the exact, unmodified official firmware for your phone's original region. If you have installed TWRP or any custom ROM (including Xiaomi.eu), do not re-lock the bootloader, as it will brick your device.
Troubleshooting & Common Errors
However, its official software support ended with a familiar story: the Chinese variant received a final, polished MIUI 12.5 update, while the Global version was left on the earlier, less stable MIUI 12.0. For enthusiasts who want to keep this unique slider flagship in pristine working order, this guide provides the path to restore it, and more importantly, to upgrade it to the best software it ever had.
This is the definitive guide for the legendary Mi MIX 3:
- ✔ An explanation of how to get the superior MIUI 12.5 update on your global device
- ✔ Download links for the final official Fastboot ROMs to unbrick and restore
- ✔ A direct link to a working TWRP custom recovery installer
- ✔ Step-by-step instructions focused on preserving this unique piece of tech
- ✔ Troubleshooting tips for the slider mechanism and other common issues
Why You Might Need to Flash Your Mi MIX 3
For a design classic like this, flashing is about preservation and optimization.
- Upgrade to the Superior MIUI 12.5 → This is the best reason to flash today. By installing a custom ROM like Xiaomi.eu (based on the China ROM), you get the bug fixes and performance optimizations that global users never officially received.
- Optimize Slider Functionality → Ensure the unique slider mechanism's software integration (shortcuts, camera launch, etc.) is as smooth and bug-free as possible by running the final, most polished software build.
- Unleash the Snapdragon 845 → A clean installation of the operating system allows the still-powerful flagship processor to run at its peak, unhindered by years of software clutter.
- Unbrick or Fix a Bootloop → The essential recovery guide for restoring a Mi MIX 3 that is stuck on the Mi logo or fails to boot.
- Create a Base for Custom ROMs → The Mi MIX 3 has a dedicated developer community. A clean flash to stock is the perfect starting point for installing newer, unofficial versions of Android.
Quick Device Overview (Codename: perseus)
- Model: Xiaomi Mi MIX 3
- Release Year: 2018
- Chipset: Qualcomm Snapdragon 845
- Display: 6.39” Super AMOLED
- Key Feature: Manual magnetic slider mechanism, ceramic back, truly bezel-less display
- OS at Launch: MIUI 10 on Android 9 Pie
- Final Official OS: MIUI 12.0 (Global) / MIUI 12.5 (China) on Android 10
- Codename: perseus
Software Notice: The Global Mi MIX 3 never officially received the final, optimized MIUI 12.5 update. To get this superior version, which fixes many bugs from the initial MIUI 12.0 release, users can install the community-made Xiaomi.eu ROM, which is based on the final China build.
Required Tools & Downloads
Download the official firmware for your region for restoration, and the necessary tools to upgrade.
| Tool / File | Purpose / OS Version | Download Link |
|---|---|---|
| Mi Flash Tool | For flashing official Fastboot ROMs. | Download Latest Version |
| Xiaomi USB Drivers | Ensures your PC can communicate with your phone. | Driver Pack |
| Mi Unlock Tool | Required to unlock the bootloader. | Official Unlock Page |
| Custom Recovery (TWRP) | Required to flash custom ROMs like Xiaomi.eu. | TWRP for Perseus (Fastboot ZIP) |
| Fastboot ROM (China) | Official MIUI 12.5 (Android 10) | V12.5.1.0.QEECNXM |
| Fastboot ROM (Global) | Official MIUI 12.0 (Android 10) | V12.0.2.0.QEEMIXM |
| Fastboot ROM (Russia) | Official MIUI 12.0 (Android 10) | V12.0.2.0.QECRUXM |
Flashing Methods
Method 1: Flashing Official MIUI 12.0 Stock ROM (Fastboot Mode)
This is the standard method for unbricking your device or restoring it to its final, official global state.
- Unlock Bootloader: Your Mi MIX 3's bootloader must be unlocked using the Mi Unlock Tool. This will erase all your data.
- Boot into Fastboot Mode: Power off your phone. Press and hold Power + Volume Down until the Fastboot logo appears.
- Extract Firmware: On your PC, extract the downloaded .tgz Fastboot ROM twice until you have a folder with an images directory.
- Launch Mi Flash Tool: Open the tool as an administrator. Click "select" and choose the extracted firmware folder.
- Connect Device & Flash: Connect your phone to the PC, click "refresh", ensure "clean all" is selected at the bottom, and click "flash".
➡ Your phone will reboot into a clean, official MIUI 12.0 system.
Method 2: Upgrading to MIUI 12.5 (via Xiaomi.eu ROM)
This is the recommended path for enthusiasts who want the best possible MIUI experience on their Mi MIX 3.
- Unlock Bootloader & Flash TWRP: Ensure your bootloader is unlocked. Extract the downloaded TWRP .zip file, boot your phone into Fastboot mode, and run the fastboot_twrp_installer.bat script.
- Boot into TWRP: Hold Power + Volume Up while the phone reboots to enter the newly installed TWRP recovery.
- Wipe Data: This is a mandatory step. In TWRP, go to Wipe → Format Data and type "yes" to confirm.
- Transfer ROM File: Find the Xiaomi.eu ROM for perseus from their official download source. Connect your phone to the PC and copy the downloaded .zip file to its internal storage.
- Install the ROM: In TWRP, tap Install, select the Xiaomi.eu ROM .zip file, and swipe the slider to begin flashing.
- Reboot: Once finished, tap "Reboot System."
➡ Your Mi MIX 3 will now run the most refined version of MIUI it ever received, free of bloatware.
FAQs
Q1: Will flashing fix the slider mechanism if it feels stuck?
No. Flashing is a software process. It can fix bugs where the slider doesn't trigger a software action (like opening the camera), but it cannot fix a physical hardware problem like a jammed or broken slider mechanism.
Q2: Can I get MIUI 12.5 on my Global Mi MIX 3 officially?
No. Support for the global version ended at MIUI 12.0. The only way to get the features and optimizations of MIUI 12.5 is to install a custom ROM like Xiaomi.eu, which is based on the final China firmware.
Q3: Is the Mi MIX 3 still a good phone in 2025?
As a daily driver, it's for enthusiasts who appreciate its unique design. The Snapdragon 845 is still powerful, but the slider adds mechanical complexity. It's a fantastic collector's item and a conversation starter that still runs modern apps well after a clean flash.
Q4: Is it safe to re-lock the bootloader?
It is only safe to re-lock the bootloader if you are returning to the exact, unmodified official firmware for your phone's original region. If you have installed TWRP or any custom ROM (including Xiaomi.eu), do not re-lock the bootloader, as it will brick your device.
Troubleshooting & Common Errors
- Bootloop after flashing a custom ROM: This is almost always because the "Format Data" step was skipped in TWRP. A simple "Wipe" is not enough. You must use the "Format Data" option to remove the stock ROM's encryption.
- TWRP installer script fails: Ensure you are running the .bat script as an administrator on Windows and that your phone is properly connected and recognized in Fastboot mode. Check the connection with the fastboot devices command.
- "The system has been destroyed": This is a generic Xiaomi boot failure message and does not indicate a hardware fault. The solution is to boot into Fastboot mode and re-flash the stock firmware.
- Mi Flash Tool "can't find file" error: This error means you haven't extracted the .tgz Fastboot ROM correctly. Ensure you extract the file twice, until you have a folder that contains the images sub-folder.