The Xiaomi Redmi 4X (codenamed santoni) remains a popular budget smartphone years after its release. However, over time, its performance may fall due to outdated software, and official updates from Xiaomi have long ceased. The device’s firmware is the only way to get current features, improve security or even resurrect a getting stuck device. But the process requires accuracy: a bug at any stage can turn the phone into a brick.
In this guide, we will analyze all methods of firmware - from official recovery through Mi Flash to install custom firmware like LineageOS or Pixel Experience. 720 hours (30 days), because it's the main barrier for most users, and you'll also find a firmware compatibility table, a checklist for preparing and solving common errors, such as Error: flash_write_failure or hanging on the Mi logo.
If you've never flashed a smartphone before, don't worry. The instructions are tailored for beginners, with every step explained and risk warnings. For power users, advanced techniques include fastboot-free firmware (where possible) and bypassing Mi Account restrictions.
1. Firmware Preparation: What You Need to Know Before You Start
Redmi 4X firmware is an irreversible process. Even if you go back to the stock version, some data (like the DRM keys for Widevine L1) can be lost forever, so the first step is to back up.
Save:
- 📱 Contacts, SMS Call log (via Mi Cloud or Adb Backup)
- 📁 Photos and videos (copy to PC or cloud)
- 🔑 Application data (passwords, game saves – use Swift Backup or Titanium Backup)
- 📋 IMEI Serial number (write on paper or take a picture of the sticker under the lid)
Also check the current firmware version in Settings → About Phone → MIUI version. This will help you choose the right file to update. For example, if you have a MIUI 10 based on Android 7, you can not immediately flash MIUI 12 for Android 9 - you will need an intermediate upgrade.
⚠️ Attention: If your Redmi is 4X purchased in China (C-suffixed version in model, for example, 2017117), firmware global version can block the network! → SIM-maps and mobile networks → Network settings.
2. Selection of firmware: official vs custom
There are three types of firmware for Xiaomi Redmi 4X:
| Type of firmware | Advantages | Deficiencies | Complexity of installation |
|---|---|---|---|
| Official MIUI (Fastboot/Recovery) | Stability, OTG support, original functionality of Xiaomi | Outdated Android, MIUI Ads, Region Restrictions | ⭐⭐ (easily) |
| Globally stable | Support for all languages, Google services out of the box | Can block networks on Chinese versions of the device | ⭐⭐ (easily) |
| LineageOS (Pixel Experience) | Up-to-date Android, no Bloatware, advanced settings | NFC, camera, or Widevine L1 may not work | ⭐⭐⭐⭐ (difficult) |
For most users, the best choice is the global stable firmware of the latest available version, which can be downloaded from the official Xiaomi website in the section MIUI Downloads.Look for the Redmi model. 4X (santoni).
If you want a custom firmware, we recommend:
- 📱 LineageOS 18.1 (Android 11) - Maximum stability
- 🎨 Pixel Experience – pure Android with Google Pixel chips
- ⚡ Havoc-OS – flexible interface configuration
Download the firmware only from verified sources:
- Official: en.miui.com
- Castomy: XDA Developers or SourceForge
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Before downloading, check the hash amount (MD5) of the firmware file! This will protect against counterfeiting. Use the md5sum utility on Linux or HashMyFiles on Windows.
3. Unlocking the bootloader: bypassing the 720-hour wait
The main obstacle to Xiaomi’s firmware is a locked bootloader. The official way to unlock through the Mi Unlock Tool requires a Mi Account to be tied and waiting up to 30 days (720 hours), but there are workarounds.
Method 1: Unlocking through EDL (Emergency Mode)
Suitable for devices that don't turn on or are stuck on the logo.
- 🔧 Cable USB Type-C with support EDL (better-than-original)
- 💻 Mi Flash Pro or QFilm
- 📄 File. prog_emmc_firehose_8917.mbn for Redmi 4X
Instructions:
- Turn off the phone.
- Press Volume up + Volume down and connect to the PC.
- The device manager should have a record of Qualcomm HS-USB QDLoader 9008.
- Run Mi Flash, select a firmware file in.tgz format and press Flash.
Method 2: Accelerated Unlocking with Mi Unlock (2026)
The current method for bypassing the 720-hour timer is:
Link Mi Account in phone settings|Enable debugging on USB In Settings → The phone. → Version. MIUI (7 times press)|Connect the phone to the PC and confirm debugging permission|Download Mi Unlock Tool latest version (not lower than 5.5.224.24)-->
Next:
- Launch the Mi Unlock Tool on behalf of the administrator.
- Sign in with the same Mi Account as you do on your phone.
- Connect your phone in Fastboot mode (clamp Volume down + Power).
- If a "Couldn't unlock" error appears, use Telegrambots to generate an unlock code (paid service, ~$5-10).
What if the Mi Unlock Tool can’t see the device?
4. Firmware via Fastboot (recommended method)
This is the most reliable way to flash the Redmi 4X, because it works even on bricks.
- 💻 Windows PC 10/11 (or Linux with fastboot installed)
- 📋 Firmware in.tgz format (for example, santoni_global_images_V12.0.2.0.NCGMIXM_20210310.0000.00_7.1_global_4a1a4d3b7f.tgz)
- 🔌 Cable USB Type-C (preferably original)
Step-by-step:
- Unpack the firmware archive into a folder without spaces (e.g., C:\MIUI\).
- Turn off the phone and press Volume Down + Power to log into the Fastboot.
- Connect your phone to your PC and check for detection by the command: fastboot devices should show a serial number of the device.
- Run the firmware with the script: fastboot flashall Or manually (if the script does not work): fastboot flash boot.img fastboot flash recovery.img fastboot flash recovery system.img fastboot flash userdata userdata.img
- After completion, execute: fastboot reboot
The first run after firmware can take 5-15 minutes – do not interrupt the process!
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Fastboot firmware completely erases data from the userdata partition (including internal memory). If you need to save files, pre-extract the memory card.
5. Firmware through Recovery (for power users)
This method is suitable for custom firmware installation or updates without data loss (if used). OTA-Important: Xiaomi's stock Recovery doesn't support installation ZIP-Files – you will need custom, for example, TWRP.
Instructions for installing TWRP:
- Download the latest TWRP for Santoni from the official website.
- Rename the file to twrp.img and place it in a folder with fastboot.
- Fastboot: Fastboot flash recovery twrp.img
- Start downloading TWRP (don’t reboot to the system!): fastboot boot twrp.img
Next for firmware:
- Copy. ZIP-Firmware file on the phone (via MTP into TWRP memory-card).
- V TWRP Choose the Wipe → Advanced Wipe and mark: 🧹 Dalvik / ART Cache 🗃️ System 📄 Data (if you need a clean installation)
Install
Wipe cache
⚠️ Note: If you have a customized ROM The phone is stuck on the screensaver, try to flash the core boot.img It's often solved by replacing the kernel with a compatible one.
6. Solving typical firmware errors
Even with the correct instructions, errors can occur, and here are the most common ways to correct them:
| Mistake. | Reason. | Decision |
|---|---|---|
| Error: flash_write_failure | Damaged system partition or incompatible firmware | Switch system.img separately with the command fastboot flash system.img |
| Hanging on the Mi logo | Incompatible core or no boot.img | Switch boot.img from another firmware or reset settings to TWRP |
| This MIUI version cannot be installed on this device | Firmware for another region or model | Download the correct version (for example, santoni_global instead santoni_china) |
| Device is locked | The bootloader is not unlocked | Unlock with Mi Unlock Tool or EDL |
If the phone does not turn on after a failed firmware:
- Try booting up to Fastboot (Loudness Down + Power).
- If you don’t respond, use it. EDL-regime (see section 3).
- In extreme cases, contact the service center with a request to flash through UFi Box or EasyJTAG.
Solution: flash modem and nvram from stock firmware or restore IMEI through Maui META.