How to flash Xiaomi Redmi 4X through Fastboot: a complete guide with errors and solutions

Fastboot is one of the most reliable ways to bring the Xiaomi Redmi 4X back to life, upgrade the system or install custom firmware. However, the process requires care: a mistake at any stage can turn a device into a brick. In this article, we will examine all the steps from unlocking the bootloader to installing the firmware, as well as typical problems and their solutions.

The Redmi 4X (codenamed santoni) is still popular today for its price-performance balance. But over time, official MIUI updates stop coming out and users face slowdowns or bugs. Fastboot firmware helps solve these problems, but it's important to understand that it's not just an "air update." It needs ADB, Fastboot, the right drivers and patience.

If you’ve never been to a smartphone before, we recommend reading each section carefully, and we’ll point out the critical points that the manufacturer is silent on — for example, why unlocking a bootloader can take up to 360 hours or how to avoid an anti-rollback error.

1. Firmware Preparation: What to Do Before Starting

Before you connect the Redmi 4X to your computer, make sure all the preconditions are met.Non-stopting at least one item can cause firmware failure or data loss.

First, check the MIUI version and bootloader number. Go to Settings → About Phone → MIUI version and tap the kernel version several times until you get a message You’re a developer!. Then go to Settings → Additional → For developers, find Mi Unlock Status. If it says Device is unlocked, you can skip unlocking. If not, you’ll have to wait.

• 📱 Save all data: Fastboot firmware erases internal memory. Use Mi Mover, Google Photos or manual copying on PC.
• 🔋 Charge the battery to at least 60%. interruption of the process due to discharge can damage system files.
• 💻 Install drivers: for Windows, download Mi Flash Tool and Qualcomm drivers (if not, Redmi). 4X Not determined in Fastboot).
• 🔗 Download the firmware: official versions MIUI For santoni available on Xiaomi Firmware Updater. Choose Fastboot firmware (file with.tgz or.zip extension).

Pay special attention to the choice of firmware version. Redmi 4X has global (Global), Chinese (China) and EEA (Europe) builds. Installing the wrong version can lead to problems with the language, Google services or mobile network. Check the current firmware in Settings → About Phone → MIUI version.

⚠️ Attention, if your Redmi 4X It was purchased in China, and Global may not support some frequencies. 4G. In this case, it is better to use China Stable with manual installation of Google Services.

2. Unlock the bootloader: why it is necessary and how to speed up the process

Xiaomi blocks the bootloader on all devices to protect users from unauthorized changes, which means that without unlocking, you can’t flash Redmi 4X through Fastboot. The process consists of two steps: linking the Mi Account to the device and unlocking it.

First, turn on OEM Unlock and USB Debugging in the Developer Menu. Then connect your phone to your PC, open the command prompt in the ADB folder, and do:

adb reboot bootloader

The device will reboot to Fastboot mode. Now start the Mi Unlock Tool (you can download from the official website), log in to your Mi Account and follow the instructions.

Here, many people are confronted with a message called Couldn't unlock: Wait 168 hours (7 days) This is the standard delay for new accounts. If you've previously unlocked other Xiaomi devices, the wait can be reduced to 72 hours. You can't get around this limit, you have to wait.

• ⏳ Unblocking time: New Mi Account: 168 hours (7 days). Account with unblock history: 72 hours (3 days). Account with tied phone number: sometimes 24 hours.
• 🔓 What to do after unlocking: Do not turn off USB-Do not log out of your Mi Account for 30 days after unlocking. Immediately after unlocking, flash the device - a long wait can lead to re-blocking.

⚠️ If you bought a Redmi, you're not going to buy it. 4X hand, make sure the previous owner untie his Mi Account from the device, otherwise unlocking will not be possible without his data.

3. Installation of drivers and setting up Mi Flash Tool

Without the right drivers, Windows won’t recognize Redmi 4X in Fastboot mode. Even if the device is defined as Android Bootloader Interface, it doesn’t guarantee stable operation. We recommend using Mi Flash Tool, the official utility from Xiaomi, which automatically installs the necessary drivers.

Download the Mi Flash Tool from the official website and install it. Then connect Redmi 4X in Fastboot mode (click Volume Down + Power when the phone is off).

1. Open Device Manager (Win + X → Device Manager).
2. Find Redmi 4X with a yellow exclamation point.
3. Right-click → Update the driver → Search on this computer.
4. Specify the path to the folder with the Mi Flash Tool installed (usually C:\XiaoMi\MiPhone).

After successfully installing the drivers, run the Mi Flash Tool. At the top of the window, click Select and select the folder with the unpacked firmware (it should contain files with the.img extension). Then press Refresh - your Redmi 4X should appear in the list of devices.

💡

If the Mi Flash Tool gives an error when unpacking the firmware, try the 7-Zip archiver. Sometimes the standard WinRAR will not properly retrieve the.img files.

4. Step-by-step: Xiaomi Redmi 4X firmware via Fastboot

Now that we're done, we can start the firmware, and it's going to take 10 to 15 minutes, but it's very consistent, and we're going to look at two options: the Mi Flash Tool, and the manual command line.

Method 1: Firmware via Mi Flash Tool (recommended for beginners):

1. Unpack the downloaded firmware in a folder without Cyrillic characters (for example, C:\MIUI\santoni_global).
2. Run the Mi Flash Tool on behalf of the administrator.
3. Press Select and specify the folder with the firmware.
4. Connect Redmi 4X in Fastboot mode (clip Volume Down + Power).
5. Press Refresh – the device should appear in the list.
6. Select firmware mode: Clean all - complete cleaning (recommended); Clean all and lock - cleaning + lock bootloader (official firmware only); Save user data - data storage (not always stable).

Flash

Method 2: Firmware through the command line (for experienced users):

1. Unpack the firmware and copy the path to the folder (for example, C:\MIUI\santoni_global\images).
2. Open the command line in the folder with fastboot (or use Platform Tools).
3. Alternately execute commands (replacing the paths on your own): fastboot flash boot.img fastboot flash recovery.img fastboot flash recovery system.img fastboot flash cache cache.img fastboot flash userdata userdata.img
4. The last command - reboot: fastboot reboot

6. firmware custom Recovery (TWRP) and custom firmware

If you want to install LineageOS, Pixel Experience or other custom firmware, you first need to flash TWRP Recovery. This is an alternative restore that allows you to install informal builds.

For Redmi. 4X (santoni) current version TWRP It's available on the official website. twrp-3.7.0_9-0-santoni.img And run it through Fastboot:

fastboot flash recovery twrp-3.7.0_9-0-santoni.img


fastboot boot twrp-3.7.0_9-0-santoni.img

After that:

1. Reboot to TWRP (click Volume Up + Power).
2. Make a backup of the current firmware (Backup) → Select Partitions → Swipe to Backup).
3. Erase the System, Data, Cache (Wipe → Advanced Wipe) partitions.
4. Install custom firmware through Install → Select ZIP.

⚠️ Attention! Castom firmware may not support Banking Apps (due to lack of SafetyNet) and some camera features. XDA Developers.

💡

Custom Recovery firmware (TWRP) It erases encryption data, if you forgot. PIN-code after installation TWRP Access to data will be lost!

7.Optimization after firmware: what to do first

After a successful firmware Redmi 4X will require initial configuration. Take your time to recover data - first make sure that the system is stable.

First, check:

• 📶 Mobile Network: If there is no signal, go to Settings → SIM-maps and mobile networks → Network settings and select mode 4G manually.
• 🔄 Updates: After the official firmware MIUI Check for updates in Settings → The phone. → Updating the system.
• 🔒 Security: Enable Find Device (Settings) → Google → Security) in case of loss of telephone.

If you have a custom firmware, install:

1. Open GApps (if they are not in the assembly)
2. Kernel Adiutor for kernel configuration (optional).
3. Titanium Backup for recovery applications (if there is a backup).

To improve performance, disable unnecessary services:

adb shell pm disable-user --user 0 com.miui.analytics


adb shell pm disable-user --user 0 com.xiaomi.ab

These commands disable Xiaomi’s analytics collection, which reduces the load on the processor.

8. Frequently Asked Questions (FAQ)