Xiaomi Redmi Note 4X firmware via Fastboot: a complete guide with nuances

The firmware of the Xiaomi Redmi Note 4X Fastboot is one of the most reliable ways to upgrade or restore a device when standard methods don't work. MIUI, A rollback to the previous version or even a transition to custom firmware like LineageOS. However, the process requires care: an error at any stage can lead to a "brick" (inoperability) of the phone.

Unlike firmware through Recovery, Fastboot works at the bootloader level, which allows you to bypass the limitations of the system. This is especially true for Redmi Note 4X (codename mido), where locking a bootloader from Xiaomi often complicates the process. In this article, we will discuss all the steps from unlocking Bootloader to the final installation of the firmware, and also consider the typical errors and how to solve them.

Preparation for firmware: what to do before the start

Before you start firmware, make sure that all the prerequisites are met, which will save time and reduce the risk of errors.

First, check out your device model. Redmi Note 4X came in a number of different versions:

• 📱 Global (firmware with global suffix) - for the international market;
• 📱 China ( cn firmware) – for China (may not support Google services);
• 📱 India (firmware with in suffix) – for India.

You can install the version in the Settings menu → About Phone → MIUI version or through the command fastboot getvar product.

Second, prepare the computer:

• 🖥️ Operating system: Windows 10/11 (recommended Linux/macOS (Additional drivers will be required);
• 🔌 USB-cable: original or high quality (cheap cables can cause connection errors);
• 📂 Free disk space: at least 5 GB for firmware and tools;
• 🔋 Battery charge: at least 60% (to avoid shutdown during the process).

⚠️ Please note: if your Redmi Note 4X If you have purchased from hand or previously downloaded, check the status of the bootloader with the command fastboot oem device-info. If the answer Device unlocked: false, you will need to unlock (see the next section).

Unlock the bootloader on the Redmi Note 4X

Without unlocking the bootloader, firmware via Fastboot is impossible – Xiaomi blocks this functionality by default.The unlocking process is official, but requires binding Mi Account account and waiting (usually 72-168 hours).

Steps to unlock:

1. Link Mi Account to your phone in Settings → Xiaomi Account
2. Activate debugging on USB unlock OEM In Settings → The phone. → Version. MIUI (Press 7 times on "Version" MIUI", Then go back to the additional settings. → For developers);
3. Download Mi Unlock Tool from the official website;
4. Connect your phone in Fastboot mode (clip Volume down + Power when the device is off);
5. Launch the Mi Unlock Tool, log in to your account and follow the instructions.

Once you send a request to Xiaomi servers, it starts counting down, you can check the status in the same tool, and if the phone was previously unlocked by another account, you will need to reset via fastboot oem. clean_all (It'll delete all the data!).

⚠️ Note: Do not use informal unlocking tools (e.g. DeepFlash or other unblocking tools). EDL). They can lead to a blockage. IMEI or "brique" device, especially on the Redmi Note 4X with a Snapdragon 625 processor.

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If the Mi Unlock Tool gives you a "Couldn't unlock" error, try connecting the phone to another one. USB-port (preferably 2.0) or use the original Xiaomi cable.

Selection of firmware: official MIUI or custom

There are two types of firmware available for the Redmi Note 4X:

• 📦 Officially MIUI — stable and weekly versions from en.miui.com;
• 🛠️ Custom – LineageOS, Pixel Experience, HavocOS (requires unlocked bootloader and installation) TWRP).

For beginners, it is recommended to start with the official MIUI. It guarantees stability and support for OTG. Custom firmware gives more freedom (for example, current Android or no advertising), but can contain bugs.

For Redmi Note 4X, it is critical to choose the firmware for the correct modification:

• 🔹 For mido (Global/China) — mido-marked firmware;
• 🔹 For mido_india — in-suffix.

Installing incompatible firmware will result in an anti-rollback or "brick" error.

Installation of drivers and tools for Fastboot

To work with Fastboot on Windows, you will need:

• 🖥️ Qualcomm drivers HS-USB QDLoader 9008 (for mode) EDL, if restoration is required);
• 📂 Mi Flash Tool – official tool for firmware through Fastboot;
• 🐧 ADB & Fastboot – Utilities for working with the phone through the command line.

Step-by-step installation:

1. Download Google’s Platform Tools and unpack it to the root of the disk C:\platform-tools\;
2. Install drivers through Device Manager (when connected phone in Fastboot mode);
3. Download the Mi Flash Tool from the official website and unpack it.
4. Check the connection with the fastboot device command – the serial number of the phone should be displayed.

⚠️ Note: If the fastboot device command does not show the device, try it: 🔄 Reconnect. USB-cable; 🔧 Update drivers manually (by specifying the folder with Platform Tools); 🖱️ Run the command line on behalf of the administrator.

Step-by-step: Redmi Note 4X firmware via Fastboot

When you're done, we're going to start the firmware, and it's going to take 10 to 20 minutes, depending on the speed. USB-port.

Step 1: Transfer your phone to Fastboot mode

1. Turn off the phone;
2. Press Volume Down + Power and hold for 5-10 seconds until the Fastboot logo appears.
3. Connect the phone to the computer.

Step 2: Launch the Mi Flash Tool

1. Open the Mi Flash Tool (XiaoMiFlash.exe file)
2. Click Select and specify the folder with the unpacked firmware (files should be with the.tgz or.img extension);
3. At the bottom, select the firmware mode: 🔄 Clean all – complete cleaning (recommended when changing version) MIUI); 🔄 Clean all and lock - cleaning + Loader lock (only for official firmware!); 🔄 save user data – saving user data (risky, can lead to bugs).

Refresh

Redmi Note 4X

Flash

Step 3: First start after firmware

After a successful firmware, the phone will restart, and it can take up to 10 minutes to launch, which is normal, if the device has been stuck on the logo for longer than 15 minutes:

• 🔄 Try to force reboot (squeeze the power for 20 seconds);
• 🔧 If it doesn’t work, repeat the firmware with a full clean (clean all).

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Always check the integrity of the downloaded firmware (the file should weigh ~1.5-2 GB). If the archive is damaged, the Mi Flash Tool will give an error critical partition flashing is not allowed.

Typical errors and their solutions

Even if you follow the instructions accurately, you can get errors.

If after firmware the phone does not turn on or hovers on the logo:

• 🔄 Try to re-sweeten with full cleaning (clean all);
• 🔧 If it doesn’t help, use the mode. EDL (Requires an authorized Xiaomi account and a special cable).

⚠️ Note: The invalid sparse file format at header error is often caused by broken firmware files. download firmware only from official sources (en.miui.com or Xiaomi Firmware Updater).

Firmware custom Recovery (TWRP) and custom firmware

If you want to install LineageOS or some other custom firmware, you first need to flash TWRP Recovery. It's an alternative recovery that allows you to install informal firmware.

Instructions for Redmi Note 4X:

1. Download the latest version of TWRP for mido from the official website.
2. Rename the file to twrp.img and place it in the platform-tools folder.
3. Connect your phone in Fastboot mode and execute the command: fastboot flash recovery twrp.img
4. Immediately after that, go to TWRP, holding Volume Up + Power (otherwise, stock recovery will overplay TWRP).

To install custom firmware through TWRP:

1. Copy the firmware (e.g. lineage-18.1-20260510-UNOFFICIAL-mido.zip) to your phone;
2. In TWRP, select Wipe → Advanced Wipe and select Dalvik, Cache, System, Data.
3. Press Install, select a firmware file and confirm the installation;
4. After completion, restart (the first start will take 5-10 minutes).

⚠️ Attention: Castom firmware may not support Xiaomi branded features such as IR port or dual apps. Before installing, check the list of working features on the forum XDA Developers.

FAQ: Answers to Frequent Questions