Xiaomi Redmi Note 4 (codenamed mido) remains one of the most popular smartphones for firmware experiments, despite the release of newer models. The reasons are different: someone wants to return “life” to an old device with custom firmware, someone needs an official update after a crash, and some just want to remove unnecessary MIUI applications. Firmware through the computer is the most reliable way, but it requires preparation and understanding of the process.
In this article, we will examine all the stages of firmware, from unlocking the bootloader to installing firmware through MiFlash or Fastboot. Particular attention will be paid to typical errors (for example, anti-rollback or “red inscription” in MiFlash), which often scare beginners. If you have never flashed a Xiaomi smartphone before, do not worry: the manual is adapted for users without a technical background, but with detailed explanations for experienced ones.
Important: PC firmware is suitable for all Redmi Note 4 modifications (including Note 4X and versions with Snapdragon 625 or Helio X20 processor). However, devices with a locked bootloader will require mandatory unlocking through the official Mi Unlock tool - we will also talk about this.
1. Firmware Preparation: What to Do Before Starting
Computer firmware is a process where little things matter, and a missed step or the wrong version of software can lead to a device being "bricked," starting with checking the current state of the smartphone and preparing the tools.
The first thing you need to do is find out the exact model and firmware version.
- 📱 Go to Settings. → About the phone and write down: Device model (e.g. Redmi Note 4 or Redmi Note) 4X). Version MIUI (for example, MIUI Global 12.5.1 Stable) Assembly number (e.g, V12.5.1.0.RMFMIXM).
- 🔍 Check the status of the bootloader: turn off the phone, press Volume down + Power: if a hare appears in a hat, the loader is unlocked. If not, you will need to unlock.
- 💾 Backup your data: firmware erases all user files. Use Mi Cloud, Google Photos or physical copying on your PC.
Also prepare the computer:
- 🖥️ Install the official Xiaomi drivers (or use Mi) PC Suite).
- 🔌 Use the original. USB-cable (poor cables may interrupt the connection).
- ⚡ Charge your smartphone by at least 50% – this will prevent a sudden shutdown during firmware.
If you are flashing your smartphone for the first time, we recommend starting with the official firmware from Xiaomi. Custom firmware (for example, LineageOS or Pixel Experience) require an unlocked bootloader and may contain bugs.
2 Unlocking the bootloader: a mandatory step for firmware
Xiaomi’s default bootloader is locked, a security measure to prevent unauthorized changes to the system.To flash the Redmi Note 4 through a PC, it needs to be unlocked.The process takes 3 to 15 days (due to Xiaomi’s policy), so start with it in advance.
Instructions for unlocking:
- Link your Mi Account to your device: 📱 Go to Settings. → Xiaomi account and log in. 🔗 B Settings → Additionally. → For developers, enable Mi Account Linking and Debugging by USB.
Mi Unlock
Mi Unlock
Mi
Fastboot
Loudness down + Nutrition
Mi Unlock
Unlock
After clicking Unlock, you may receive a waiting message (e.g., “72 hours left”). This is normal – Xiaomi limits unlocking for security. Repeat every 24 hours until you receive a message about successful unlock.
What happens if you flash a smartphone with a locked bootloader?
⚠️ Warning: If you bought the Redmi Note 4 with your hands, make sure the previous owner untie your Mi Account from the device. Otherwise, unlocking will not be possible without its data.
3. firmware selection: official MIUI vs custom builds
The stability of the smartphone depends on the choice of firmware. Official MIUI firmware is suitable for most users, and custom ones (for example, LineageOS or AOSP) are suitable for enthusiasts ready for possible bugs.
| Type of firmware | Advantages | Deficiencies | Where to download |
|---|---|---|---|
| Official MIUI Stable | Maximum stability support OTA-Updates All camera and sensor functions are working | Advertising in system applications Unnecessary services Xiaomi | Official website |
| Official MIUI Beta | New features before all Cleaner system (less advertising) | Possible bugs and unstable operation No OTA for some regions | Xiaomi.eu |
| Castomium (LineageOS, Pixel Experience) | Clean Android Ads-Free Long-Term Support (Security Updates) | Camera may not work or NFC may not have official support | XDA Developers |
For the Redmi Note 4 (mido), we recommend the following builds:
- 📦 Official stable: MIUI Global 12.5.8 Stable (last version for mido).
- 🧪 Advertising free: Xiaomi.eu (weekly builds with optimizations).
- 🤖 Pure Android: LineageOS 18.1 (based on Android 11) or Pixel Experience (with an interface from Google Pixel).
When choosing custom firmware, look for the anti-rollback version. Redmi Note 4 has rollback protection against older firmware. If you install firmware with a lower anti-rollback number than the current firmware, the device will lock. You can find out the current number in Fastboot by command:
fastboot getvar anti4. Firmware through MiFlash: step-by-step instructions
MiFlash is Xiaomi’s official firmware utility for Fastboot devices, and is suitable for installing official firmware (in.tgz or.zip format) and recovering your smartphone after a crash.
What you need:
- 🖥️ Windows computer (7/10/11).
- 📱 Smartphone with unlocked loader and charge ≥50%.
- 🔌 Original. USB-cable.
- 📦 Firmware in.tgz format (download from the official website).
- 🛠️ MiFlash (version 2020 or later).
Instructions:
- Unpack the downloaded firmware in a folder without Cyrillic characters (for example, C:\MIUI\mido_global_images_...).
- Install MiFlash and run on behalf of the administrator.
- Turn off your smartphone and turn to Fastboot mode (clip Volume down + Power).
- Connect your phone to your PC. In MiFlash, press Refresh, and a device (e.g., COM3) should appear.
- In the Select field, specify the path to the folder with unpacked firmware.
- Select firmware mode: Clean all - complete cleaning (recommended when changing the version of MIUI), Clean all and lock - cleaning + lock bootloader (only for official firmware!), Save user data - saving user data (not always stable).
Flash
Make sure the loader is unlocked|Check the firmware version (not lower than the current one)|Disable the antivirus (it can block MiFlash)|Use the back. USB-port (for stable connection)|Do not disconnect the cable until the process is complete.-->
After successful firmware, the smartphone will automatically restart. The first launch can take up to 10 minutes, which is normal. If the process has been stuck on the MI logo for longer than 15 minutes, try reflashing the smartphone in Clean all mode.
⚠️ Warning: If the red word Flash Done. Unlock Fail appears in MiFlash, it means that the bootloader has not been unlocked. Repeat the unlock process (section 2) and try flashing again.
5. Firmware through Fastboot: an alternative method
If MiFlash doesn't work, or you want to install custom firmware, you can use Fastboot manually, which requires knowledge of commands, but gives you more control over the process.
What you need:
- 🖥️ PC with installation ADB and Fastboot.
- 📦 Firmware in.tgz format (for official) or.img-files (for customization).
- 📝 List of commands for your firmware (usually attached to the archive).
Instructions for official firmware:
- Unpack the firmware in a folder (for example, C:\MIUI\images).
- Open the command line (Win + R → enter cmd) and go to the firmware folder: cd C:\MIUI\images
- Connect your phone in Fastboot mode and check the connection: fastboot devices should show a serial number of the device.
- Run the firmware command: fastboot flash all or separately for each partition (for example, fastboot flash boot.img).
- After completion, restart your smartphone: fastboot reboot
For custom firmware (e.g. LineageOS), the process is similar, but instead of flash all, separate commands are used for each partition (boot, system, vendor, etc.).
💡
If the firmware through Fastboot is interrupted with an error FAILED (remote: 'Partition not found', check the name of the partition in the command. 4 The correct name for the system partition is system, not system. system_image.
Typical errors and their solutions
Even if you follow the instructions, you can make mistakes, and let's look at the most common ones and how to fix them.
| Mistake. | Reason. | Decision |
|---|---|---|
| anti-rollback check fail | Try to install firmware with a lower anti-rollback number than the current one. | Install firmware with an equal or higher anti-rollback number. Check the current number with the command fastboot getvar anti. |
| The Red Sign in MiFlash (Flash Done. Unlock Fail) | The bootloader is not unlocked or linked to another Mi Account. | Re-unblock through Mi Unlock (Section 2). If your account is not yours, contact the previous owner. |
| This package is for "mido" devices; this is a "" | The firmware is not suitable for your model (for example, try flashing the Note 4X with the Note 4 firmware). | Download the firmware for your model (mido for Redmi Note 4/4X). |
| The smartphone does not turn on after firmware ("brick") | Incorrect firmware, interrupted process, or incompatible version of anti-rollback. | Try flashing official firmware through MiFlash in Clean all mode. If it doesn't work, contact the service. |
If the smartphone boots after firmware, but there are problems (for example, the camera or mobile network does not work), most likely, the firmware is incompatible with your modification of the Redmi Note 4.
- 🔍 Check the exact model in Fastboot with the command: fastboot getvar product (must return mido).
- 📥 Download the firmware for your modification (for example, for Note). 4X with a Snapdragon 625 or Helio processor X20).
- 🔄 Repeat the firmware with full cleaning (Clean all).
💡
If the smartphone does not turn on after firmware, do not panic: in 90% of cases it can be restored by re-running through Fastboot. The main thing is not to turn off the cable and do not try to turn on the power button device during the process.
7. Data recovery after firmware
Firmware via MiFlash or Fastboot erases all user data, including photos, contacts and apps, but some of the information can be recovered if you back up.
Recovery methods:
- 📱 Contacts and Notes: If you sync them with your Mi or Google account, they will be restored automatically after you sign in.
- 📷 Photo and video: If you used Google Photos or Mi Cloud, you can download the files back. DCIM on a memory card (if it is not formatted).
- 🎮 Apps and Settings: Restore from Mi Cloud backup (if it was created before firmware) or manually install apps from Google Play.
- 📄 Documents: Check Download and Documents folders on a memory card or in cloud storage.
If there is no backup, you can try to restore data using programs like Dr.Fone or Recuva, but the chances are small - the firmware through Fastboot completely overwrites the memory partitions.
⚠️ Note: If you have installed custom firmware (such as LineageOS), restore backup MIUI It can lead to conflict, and in this case, it's better to set up your smartphone from scratch.