Owners of budget smartphones often face the fact that the official support of the device ends faster than you would like. Xiaomi Redmi 9, released on the basis of the processor MediaTek Helio G80, is an excellent candidate for experimentation, as its standard shell MIUI can seem excessively heavy. Installing custom operating system allows you to significantly speed up the interface, get a clean Android and extend the life of the gadget for several years.
The process of replacing software requires care, but the result is worth it: you get SuperUser rights, the ability to remove system debris and install modules that change the kernel of the system, but it is worthwhile to understand that any manipulation of memory partitions carries risks, so you need to approach the procedure prepared.
In this article, we’ll break down the steps from unlocking the bootloader to the first boot in a new system. We use proven tools and techniques relevant to the MT6769V/CU architecture to ensure compatibility with your device. Take your time, read every step and check files before downloading.
Preparation of the device and necessary tools
Before you start any action, you need to assemble a full arsenal of software. USB-cable, preferably original or certified, as cheap counterparts often do not support data transfer in Fastboot mode. Also make sure that the battery charge is at least 60%, so that a sudden shutdown does not turn the phone into a “brick».
The computer must have ADB and Fastboot drivers installed. Without them, the computer will not be able to properly interact with the smartphone bootloader. Windows users often need to additionally install MediaTek VCOM drivers, which are activated when the phone is turned off.
☑️ Checklist before firmware
Remember to make a full backup of all important data. During the process of unlocking the bootloader, all data on the phone will be permanently deleted. Save photos, contacts and documents to the cloud storage or to an external hard drive.
Unlocking the bootloader (Unlock Bootloader)
The first and mandatory step is to unlock the bootloader. Xiaomi blocks this feature by default, requiring confirmation through the servers. You need to link your Mi Account in your phone settings and apply for unlock through the official Mi Unlock Tool utility.
You'll have to wait 7 to 168 hours after you file, which is the time you need to check your server account, and once that's over, you can go to unlock, turn off your phone, press Volume Down + Power, and connect the cable to your PC.
⚠️ Note: Once the bootloader is unlocked, some of Google Pay’s banking apps and services (now Google Wallet) will stop working as standard.
Launch the Mi Unlock Tool, log in to the same account you had on your phone, and press the unlock button. It takes a few minutes, after which the device will restart and clear the data. Now the path to installing the modified TWRP backup is open.
Installation of custom TWRP Recovery
The standard recovery menu does not allow you to install third-party firmware files. We need a TWRP (Team Win Recovery Project) adapted specifically for Redmi 9. Download the current.img file from a trusted source, for example, from the 4PDA forum or the official developer website.
Place the recovery file in the ADB tool folder on your computer. Put your smartphone into Fastboot mode (as described above) and connect it to your PC. Open the command line in the ADB folder and enter a command to check the connection:
fastboot devicesIf the serial number of the device appears in the line, the connection is established. Now you need to flash the image of the Recovery, and it is important to prevent the phone from rebooting to the system before installation, otherwise the standard recap will overwrite TWRP.
fastboot flash recovery twrp-redmi9.imgAfter successful firmware, you need to immediately put the phone into recovery mode. On some Xiaomi devices, you need to pin the Volume up + Power immediately after the command is completed until the screen goes out.
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If TWRP requires a password after installation, enter the unlock password for your smartphone screen. If the password doesn't fit, you may need to format the data via the Wipe menu.
Custom firmware installation process
The file of the operating system itself (e.g. LineageOS, Pixel Experience or custom build) MIUI) You need to download in advance and place in the internal memory of the phone or on the phone. SD-I've loaded it in. TWRP, First, backup your current system through the Backup menu in case something goes wrong.
Next, we'll go to partition cleanup. Select Wipe → Advanced Wipe and tick Dalvik, Cache, System, Data. Don't touch the Internal Storage if the firmware file is there, or the installation will stop. After cleaning, confirm the swipe.
| Section | Action. | Risk of data loss |
|---|---|---|
| Dalvik / ART Cache | Wipe | No (app cache only) |
| System | Wipe | Yes (removes OS) |
| Data | Wipe | Yeah (deletes photos, contacts) |
| Internal Storage | Don't touch it. | Critical (file deletion) |
Go back to the main menu and select Install. Find the firmware archive and swipe to confirm the installation. It takes a few minutes. If you plan to use Google services, immediately after you have installed the OS without restarting, install the GApps package of the same version of Android.
What are GApps and why do they need them?
Getting Root Rights through Magisk
One of the main goals of a firmware change is often to gain superuser rights. APK-Magisk file, rename its extension to.zip and run through TWRP sympathetic.
Once installed and first downloaded, the Magisk icon will appear in the app menu, open it and allow all the rights requested, and now you can control the access of applications to system files and hide the presence of root rights from banking programs.
Full functionality may require Zygisk to be enabled in Magisk settings, which will allow you to use modules that are embedded in the system processes. Remember that with greater rights comes a great responsibility: deleting system files without knowledge can lead to the failure of the phone.
⚠️ Note: When you update the firmware to a new version, Magisk will be removed. You will have to re-stitch the patched image or ZIP-Magic file through the recovery after each system update.
Possible errors and their solution
For example, an Error 7 error when installing a zip archive often means an incompatible Android version or a corrupted download file. Check the integrity of the downloaded archive and the model's compliance (the code name lancelot for the global version).
If your phone is stuck in a boot loop, try logging into TWRP and doing Wipe Data/Factory Reset. If that doesn't help, you may need to return to the official firmware via the Mi Flash Tool in Clean All mode.
Camera or sound problems in custom firmware are solved by installing special patches or using alternative applications optimized for a specific kernel.
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The key to success is the exact matching of your device’s firmware files.Redmi 9T or Redmi 9C will kill your Redmi 9.