Why Redmi 4X is not getting Android 9 officially and what to do about it
Xiaomi Redmi 4X (codename santoni) was released in 2017 with Android 6.0 Marshmallow on board and later received an update to Android 7.1 Nougat under MIUI 9/10. However, official support for the device ended at this stage - Xiaomi did not release for the model Android 8 Oreo or Android 9 Pie through standard channels. The reasons lie in hardware limitations: the smartphone is equipped with a Qualcomm Snapdragon 435 chipset and only 2/3 GB of RAM, which makes it not powerful enough for stable operation of new versions of the OS.
However, it is possible to upgrade Redmi 4X to Android 9, but only through informal firmware (custom ROMs), which requires unlocking the bootloader, installing custom backups and manual firmware. The process is fraught with risks, but gives access to the latest features: improved multitasking, adaptive brightness, navigation gestures and updated applications. In this article, we will examine both how to check the current version of the software and why the official update is not available, and describe in detail the process of installing Android 9 through custom firmware.
Before you start, consider: unofficial firmware can contain bugs, and improper actions lead to a “brick” (complete failure) of the device. If you are not ready for experiments, consider alternatives: optimizing the current version of MIUI or buying a new smartphone.
Check the current version of Android and MIUI on Redmi 4X
Before upgrading, you need to accurately determine the firmware version and device model. On Redmi 4X, this is done through the settings menu:
- Open the Settings app (cog icon).
- Go to the About Phone section.
- Scroll down to MIUI version – the current firmware is listed here (e.g. MIUI Global 10.2.3.0 | Stable).
- Click a few times on the Android version bar to see the build number (e.g. NRD90M for Android 7.1.2).
Also check the code name of the device, which must match the santoni.
- Install the CPU-Z app from Google Play.
- Open the Device tab and find the Model bar, which should indicate Redmi 4X (santoni).
If your device meets the parameters (Santoni, Android 7.x), you can start preparing. Otherwise, (for example, if you have a Redmi 4 or Redmi 4A), the instruction will not work – firmware for different models is incompatible!
Preparation for the update: unlocking the bootloader and backup
Installing custom firmware requires unlocking the bootloader, which erases all data on the device, so first make a backup:
- 📱 Contact and SMS: sync with your Google account or export through apps like Super Backup.
- 📷 Photo/video: copy to PC or cloud (Google Photos, Yandex Drive).
- 🔑 Applications and settings: Use Settings → Additionally. → Backup and reset (but recovering data after a firmware change is not always possible!).
- 📋 IMEI Serial number: write them down (you can find them under the battery or in Settings) → The phone).
To unlock the loader:
- Link the device to your Mi Account in Settings → Xiaomi account.
- Go to the Mi Unlock website and download the Mi Unlock Tool.
- Enable Developer Mode (click 7 times on Version) MIUI in settings) and activate OEM-unlocking and debugging USB.
- Connect your phone to your PC, launch the Mi Unlock Tool, and follow the instructions. It takes up to 72 hours (you have to wait). SMS-confirmation from Xiaomi).
⚠️ Warning: Unlocking the bootloader will cancel the warranty and erase the data. If the device was purchased on credit or lease, check with the seller whether you are violating the terms of the contract.
Synchronized contacts and photos|Backup made. IMEI|Drivers installed ADB|Xiaomi account confirmed by SMS|Debugging by USB included-->
Firmware Choice: Official Alternatives vs Custom ROMs
Since Xiaomi didn’t release Android 9 for the Redmi 4X, you have two options:
| Type of firmware | Advantages | Deficiencies | Examples |
|---|---|---|---|
| Official ports of MIUI | Stability, OTG support, camera runs bug-free | Android 7.1 – The maximum available | MIUI 10/11 for Santoni |
| Castomy AOSP-firmware | Android 9/10, pure Android without bloatware, regular updates | Fingerprint sensor, camera, NFC may not work | LineageOS 16, Havoc-OS, Pixel Experience |
| MIUI-based firmware | Retained functionality Xiaomi, updated Android | Rare updates, possible bugs | MIUI 12 with Android 9 (unofficial builds) |
For Android 9 Pie, we recommend:
- 📱 LineageOS 16 is the most stable AOSP-firmware with minimal bugs.
Critical: Firmware for Redmi 4X on Android 9 often doesn’t support hardware video acceleration (playing Full HD can be lagging) and has power consumption problems due to the lack of optimized drivers from Qualcomm.
Step-by-step: Install Android 9 via TWRP
To install custom firmware, you will need a custom TWRP Recovery. Follow the instructions:
1. Installation of TWRP
Download the latest version of TWRP for santoni from the official website twrp.me.
- 🔗 ADB and Fastboot (link).
- 📦 Firmware (e.g. LineageOS 16 for Santoni).
- 🤖 GApps (Open GApps Package for the ARM64, Android 9, a pico variant).
Next:
- Unpack the platform-tools in the root of the C:\ disk.
- Move the twrp-3.6.2-santoni.img file to the same folder.
- Connect your phone in Fastboot mode (turn off the device, press Volume Down + Power).
- Open the command line in the folder with platform-tools and execute: fastboot flash recovery twrp-3.6.2-santoni.img fastboot boot twrp-3.6.2-santoni.img
2. LineageOS 16 firmware
On the TWRP menu:
- Click on Wipe → Advanced Wipe and tick Dalvik, Cache, System, Data.
- Return to the main menu, select Install and swipe through the firmware first, then GApps.
- After installation, run Wipe → Format Data (required!), then restart.
⚠️ If after the reboot the phone is stuck on the logo for more than 10 minutes, then the firmware is incompatible with your modification Redmi. 4X (For example, you have a version with 16 GB of storage and firmware with 32 GB. Try a different build.
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If the camera doesn’t work after Android 9 is installed, download the GCam module for the Snapdragon 435 from the 4PDA forum and install it through Magisk.
Solving problems after updating
Even successful firmware can come with bugs, and let's look at typical problems and their solutions.
| Problem. | Possible cause | Decision |
|---|---|---|
| The mobile network is not working | Absent. IMS-modules for Android 9 | Install the VoLTE Fix patch for santoni via Magisk |
| Fast battery discharge | Unoptimized core | Install the FrancoKernel kernel or roll back to Android 7 |
| The fingerprint sensor is not working. | Lack of drivers in AOSP | Use it. PIN-code or run the firmware on the base MIUI |
| Lags when playing video | No hardware decoding | Install MX Player with SW Decoder setting |
If the device is not turned on after the firmware:
- Press Volume Up + Power for 10 seconds for forced reboot.
- If it doesn’t work, connect to your PC and run in Fastboot: fastboot erase userdata fastboot reboot.
- In extreme cases, run the original firmware through the Mi Flash Tool (instructions on xiaomiflash.com).
What to do if your phone is stuck in a bootloop?
Alternatives: How to Improve Performance Without Updating
If the firmware risks seem too high, consider alternative ways to optimize the Redmi 4X:
- ⚡ Turn off animations: in Settings → About the phone, press 7 times on the version MIUI, Then in the Developer Settings, install Windows Animation = 0.5x.
- 🧹 Clean up the boot: use Greenify or manually disable background processes in Settings → Battery → Optimization.
- 🔄 Install a light firmware: for example, MIUI 10 instead MIUI 12 - It consumes less resources.
- 📵 Replace Facebook with Hermit Lite and Chrome with Bromite.
You can also install Xposed Framework (for Android 7) and modules like GravityBox to fine-tune the interface, but this requires root rights, which also voids the warranty.
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Upgrading to Android 9 on Redmi 4X is only advisable if you need new features critically (e.g. support for modern apps).