How to Reflash Xiaomi Redmi 4X via Fastboot: A Complete Guide from Unlocking to Installing Firmware

Xiaomi Redmi 4X (codenamed santoni) remains a popular budget smartphone even years after its release. However, over time, standard MIUI firmware begins to slow down and official updates stop coming out. Fastboot flashing is a reliable way to get the device back on track, install a fresh version of Android or even custom firmware like LineageOS. But the process requires care: a mistake at any stage can turn the phone into a brick.

In this guide, we will look at all the steps of flashing from unlocking the bootloader to installing the firmware through MiFlash, and focus on common errors (such as anti-rollback or invalid image) and how to solve them. If you have never flashed a smartphone before, don’t worry: the manual is adapted for beginners, but with technical nuances that are often missed in simplified guides.

Preparation for Flashing: What You Need to Know Before You Start

Fastboot flashing is not just about downloading new software, it's about completely rewriting the system partitions of a smartphone, which requires some preparation, and here are the key things that often cause failure:

• 🔓 Unlocking the bootloader is a must for all Xiaomi devices. Without it, MiFlash will not be able to record firmware.
• 📱 Data retention: Flashing erases everything, including photos, contacts and apps. Use Mi Cloud or manual copying on PC.
• 🔋 Battery charge at least 60%. interruption of the process due to discharge can damage the loader.
• 🖥️ Drivers and software: MiFlash should be installed on PCs, ADB/Fastboot tools and drivers for Redmi 4X.

One of the most common questions is, "Can I flash Redmi 4X without unlocking the bootloader?" The answer is no. Xiaomi blocks the bootloader on all devices, and without official permission (via the Mi Account), firmware through Fastboot is impossible. Attempts to circumvent this restriction lead to the error device is locked.

⚠️ Attention: If your Redmi is 4X If you have been bought by hand, make sure that the previous owner untie the Mi Account from the device. Otherwise, unlocking the bootloader will not be possible without its data.

Also check the firmware version on your phone (Settings → About Phone → MIUI Version).If it is older than MIUI 10, you may need to upgrade pre-update through Updater to avoid compatibility errors.

Unlocking the bootloader on Redmi 4X: step-by-step instructions

Unlocking the bootloader is the most important step. Xiaomi requires you to link the device to your Mi Account and wait 7-30 days (depending on the company's policy).

1. Link your Mi Account to your phone: Go to Settings → Mi Account → Sign in. Make sure your device is linked to your account (the Mi Cloud section should show the model name).

Once a request is submitted, Xiaomi will start counting down (usually 168 hours), and trying to unlock the bootloader ahead of time will lead to the Couldn’t unlock error, and the only way to speed up the process is to use an account that has already unlocked other devices before.

⚠️ Warning: If Mi Unlock shows an error Current account is not bound to this device, then the account is not tied to the phone.

Once successfully unlocked, the phone will automatically restart with a warning: This device is unlocked.

Linked to Mi Account on phone|On. OEM-unlock|Debugging is on. USB|Phone's 60-charged%+|Downloaded utility Mi Unlock-->

Firmware selection for Redmi 4X: official MIUI vs custom options

The firmware choice is critical to the stability and functionality of the device, and there are three types of firmware available for the Redmi 4X (santoni):

For most users, the best choice is the official Stable version of MIUI, which can be downloaded from en.miui.com (select Redmi 4X and Global region), and if you want Android 10+, you'll have to consider custom options, but be prepared for loss of functionality.

Important: firmware for Redmi 4X is divided into two types by processor:

• 📌 santoni – for models with Snapdragon 435 (most devices).
• 📌 prada - for Chinese versions with other iron (rarely found).

Installing firmware not for your model will lead to hard brick (irreparable damage).

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Before downloading the firmware, check its hash (MD5) to avoid errors when unpacking the archive. Compare the hash with the official one on Xiaomi or the 4PDA forum.

Install firmware through MiFlash: detailed instructions

Now, let's get to the firmware process itself.

• 🖥️ Windows computer (7/10/11).
• 📱 Redmi phone 4X loader-free.
• 🔌 Cable USB Type-C (preferably original).
• 📁 Firmware in.tgz format (unpacked in folder).
• 🛠️ MiFlash utility (version 20180528 or later).

Step 1. Preparation of firmware

Downloaded archive with firmware (for example, santoni_global_images_V12.0.1.0.QCMMIXM_20210112.0000.00_10.0_global_1234567890.tgz) You need to unpack into a folder without Cyrillic characters (for example, C:\santoni_fastboot\). Inside should be an image folder with.img files.

Step 2: Launching MiFlash

Open MiFlash on behalf of the administrator. In the Select field, specify the path to the folder with the unpacked firmware. Phone should be turned off. Press Volume down + Power to log into Fastboot (there will be a hare in a hat-eared on the screen). Connect the phone to a PC.

Step 3. Firmware settings

In MiFlash, at the bottom, select one of three modes:

• 🔄 Clean all – complete cleaning (recommended for changing Android version).
• 🧹 Clean all and lock - cleaning + bootloader lock (use if you are selling your phone).
• 🔧 Save user data – saving user data (not always working correctly).

Step 4: Starting the firmware

Press Refresh, your Redmi 4X should appear on the device list (if not, check the drivers). Then click Flash. It takes 5-10 minutes. Success will appear in the log when it is completed, and the phone will restart.

⚠️ Warning: If MiFlash gives you a flash not done error, check: Is the path to the firmware correctly indicated (should be an image folder, not an archive) is the phone connected in Fastboot mode (not in Recovery!). Is there any Cyrillic characters or spaces on the way to the folder.

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Use only the original USB cable – cheap analogues can cause data transmission errors and interrupt the firmware.

Typical Redmi 4X firmware errors and their solutions

Even with the correct instructions, errors can occur, and here are the most common ways to correct them:

The anti-rollback error is especially insidious, and it occurs when you try to roll back to an older version of MIUI than the one that was installed earlier. Xiaomi blocks this at the bootloader level. The only solution is to flash the new version (for example, from MIUI 11 to MIUI 12), but not vice versa.

If after firmware the phone is getting stuck on the Mi logo or rebooting in a cycle, try:

1. Reset settings via Recovery (Loudness up + Power → Wipe Data).
2. Repeat the firmware with the choice of clean all option.
3. Check the firmware compatibility with your model (Santoni vs prada).

Custom Recovery (TWRP) firmware for unofficial firmware installation

If you plan to install LineageOS, Pixel Experience or other custom firmware, you need to flash first. TWRP Recovery. It's an alternative recovery that allows you to install ZIP-firmware.

Step 1 Download TWRP for Redmi 4X

The official version can be found on the website twrp.me (file) twrp-3.6.2_10-0-santoni.img). To simplify the process, you will also need the fastboot utility (included in Platform Tools).

Step 2: Installation of TWRP

Connect your phone in Fastboot mode and execute the command in the command line (from the folder with fastboot):

fastboot flash recovery twrp-3.6.2_10-0-santoni.img


fastboot boot twrp-3.6.2_10-0-santoni.img

After that, the phone will load into TWRP. Important: immediately make a backup of the persist partition to avoid problems with IMEI after firmware custom.

Step 3: Custom firmware firmware

Downloaded ZIP-copy a firmware file (for example, LineageOS) to a phone or flash drive. TWRP execute:

1. Wipe → Advanced Wipe (mark Dalvik, Cache, System, Data).
2. Install → choose ZIP-firmware.
3. After installation, run GApps (if you need Google services).
4. Reboot System.

⚠️ Note: Castom firmware often breaks the job IR-blaster NFC on the Redmi 4X. If these functions are critical, stay on MIUI.

What to do after firmware: setup and optimization

After the first load of the new firmware, you need to follow several steps to ensure that the device works stably:

• ⚙️ Reset the settings to factory (if stitched through clean all): Settings → Additionally. → Recovery and discharge.
• 🔄 Update your firmware to the latest version through Settings → Updating the system (relevant to the MIUI).
• 🛡️ Disable unnecessary system applications (e.g. Mi Video, Mi Music) via Settings → Annexes.
• 📱 Configure developer rights to optimize performance (turn off animations, turn on Force) GPU rendering).

If you have flashed custom firmware (for example, LineageOS), additionally:

• Install Magisk for root rights (if necessary).
• Check IMEI (type *#06#). If IMEI is lost, restore it via TWRP (persistent partition backup).
• Calibrate the battery (discharge to 0%, charge to 100% without interruptions).

To check the stability of the firmware, use the tests:

• 📊 AnTuTu Benchmark – Performance Assessment.
• 🔋 AccuBattery – Monitoring battery consumption.
• 📡 Network Signal Guru – Checking the Wi-Fi Module.

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After the custom firmware is installed, the device can warm up and discharge quickly for the first 2-3 days, which is normal. Give the system time to optimize.

FAQ: answers to frequent questions about the Redmi 4X firmware