Reflashing Xiaomi Mi 9A: official and custom methods

Xiaomi Mi 9A (codenamed cepheus) is a popular smartphone with a balance of performance and price, but even it requires a firmware update over time. You may have experienced slowdowns after upgrading to MIUI 14, want to install custom software like LineageOS or return the factory version after a failed experiment. In this article, current firmware methods for 2026, including bypassing Xiaomi’s new restrictions on unlocking the bootloader.

A mistake at any stage (from choosing the wrong version of software to interrupting installation) can turn a device into a brick. We will consider three main ways: through a regular MIUI Updater, manual installation in Recovery, and full firmware reflash through Fastboot. Special attention will be paid to preparation — without unlocked bootloader and the right drivers, even the official firmware will not stand up.

Warning: After the firmware resets all data (including photos in internal memory), and the Xiaomi warranty is canceled.If your goal is just to update the system, first check for OTA- updates in Settings → About Phone → Update MIUI.

1. Firmware preparation: unlocking the bootloader

The first and most critical step is to unlock the bootloader. Without this, you can not install custom software or even official firmware through Fastboot. Xiaomi has tightened the rules: now you need to link your Mi Account to the device and wait 7 days after the first binding.

What you need:

• 📱 Xiaomi Mi 9A with a battery charge ≥ 60%
• 💻 A computer on Windows/Linux with ports USB 2.0 (USB 3.0 may cause errors)
• 🔌 Cable USB Type-C (original or certified)
• 🔑 Mi Account with a confirmed phone number

Instructions for unlocking:

1. Activate Developer Mode: Go to Settings → About Phone and click on MIUI Version 7 times.
2. Return to Settings → Additional → For developers and enable: Debugging by USB Unlock OEM (if you do not have an option, connect to the Internet and restart your phone)

Mi Account

Settings → Xiaomi Account → Link your account to your device

Official utility Mi Unlock

Fastboot

Power + Volume reduction

Mi Unlock

⚠️ Warning: Once the bootloader is unlocked, the smartphone will perform a hard reset. Save data to an external drive or to the cloud in advance. Also note that some banking applications (such as SberBank Online) may stop working on unlocked devices.

2. Selection of firmware: official vs custom

The hardware type is the type of device and the risk. Official versions of MIUI are stable but contain ads and redundant services. Custom versions (like LineageOS or ArrowOS) are devoid of this, but may have camera or NFC bugs.

For Xiaomi Mi 9A (cepheus), we recommend the official MIUI Stable for everyday use or LineageOS 20 (based on Android 13) for enthusiasts. Avoid firmware marked "Port" or "Unofficial" - these often contain critical bugs.

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Before downloading the firmware, check its hash (MD5) using the CertUtil utility in Windows or the md5sum command in Linux. This will save you from corrupted files that can interrupt the installation process.

3. firmware via MIUI Updater (without unlocking)

The safest method is to upgrade through the built-in MIUI Updater app, which is suitable for installing official versions of MIUI without losing data, but has limitations:

• 🔄 You can only upgrade to a newer version (downgrade prohibited)
• 📥 Requires a stable internet connection (Wi-Fi recommended)
• ⏳ The process can take up to 30 minutes.

Step-by-step:

1. Open Settings → About the phone → Update MIUI.
2. Click on the icon “⋮” in the upper right corner and select Select the firmware file.
3. Specify the path to the downloaded firmware file (.zip format, the name should contain cepheus).
4. Confirm the installation and wait for the reboot. The Mi logo will appear on the screen with a progress lane.

If the update is delayed during the Verifying Update Package, try:

• Rename the firmware file to update.zip and try again.
• Disable Signature Verification in TWRP Recovery (if installed).
• Use a different firmware file (e.g., from another mirror).

⚠️ Warning: If your phone is bootlooped after upgrading via MIUI Updater, reset via Recovery: Press Power + Volume Up, select Wipe Data → Reboot.

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Update via MIUI Updater saves user data, but may not work if the firmware is designed for another region (for example, trying to install MIUI EU on the Chinese version of the smartphone).

4. Firmware through Recovery (TWRP)

The method is suitable for installing custom firmware or official versions of MIUI in.zip format. You need to install custom recovery - for example, TWRP. Official Mi Recovery does not support the installation of unofficial firmware.

What to do before you start:

Download firmware (.zip) and place it on a SD- card or internal memory |Install TWRP for cepheus (3.7.0 version or later) | Download Magisk (if needed root) |Check battery (≥ 70%) |Deactivate the screen lock (PIN/ password)

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Installation instructions:

1. Reboot your phone to Fastboot (Power + Volume Down).
2. Connect to your PC and execute the command to install TWRP: fastboot flash recovery twrp-3.7.0-cepheus.img fastboot reboot recovery
3. In TWRP, run Wipe → Format Data (required for custom firmware!).
4. Select Install, specify the firmware file and confirm the installation.
5. After completion, press Reboot System.

If the phone hangs on the Mi logo after the reboot, go back to TWRP and:

• Install Disable_Dm-Verity_ForceEncrypt.zip (unless the firmware is AOSP).
• Check firmware compatibility with your model (cepheus for Mi 9A).
• Repeat the installation by pre-formatting the System partition.

5. Full firmware via Fastboot (for experienced)

Fastboot is the most reliable method for recovering a bricked-up device or installing an official firmware from scratch, erasing all partitions and installing a clean system, and it's important that it requires an unlocked bootloader and the right sequence of commands.

Files required:

• 📁 Firmware in.tgz or.zip format (e.g. cepheus_global_images_V14.0.2.0.TFAMIXM_20231010.0000.00_12.0_global.zip)
• 🛠 The Mi Flash Tool (download from the official website)
• 🔌 Qualcomm HS-USB QDLoader 9008 drivers (unless the phone is identified in Fastboot)

Step-by-step:

1. Unpack the firmware in a folder without Cyrillic characters (for example, C:\MIUI\cepheus).
2. Open the Mi Flash Tool, press Select and point the path to the firmware folder.
3. Connect the phone in Fastboot mode (turn off, then press Power + Volume Down).
4. In the Mi Flash Tool, select Clean All (full clean) or Clean All and Lock (if you want to lock the bootloader after firmware).
5. Press Flash and wait until it is completed (the process will take 5-10 minutes).

Typical errors and decisions:

⚠️ Warning: If your phone doesn't turn on (black screen) after you run through Fastboot, plug it into charging for 30 minutes -- sometimes the battery runs out during the process. If that doesn't work, repeat the firmware with the Clean All and Lock option.

6. Solving problems after firmware

Even if you successfully install firmware, you can have problems, and let's look at typical scenarios and how to fix them.

1 problem: Phone does not detect SIM- card

Reasons:

• 📶 Firmware for another region (e.g., MIUI CN on a global model).
• 🔧 Modem partition is damaged (occurs when the firmware is interrupted).

Decision:

1. Install firmware for your region (check by the label in the file name: global, eea, ru).
2. In Fastboot, file modem.img and fsg.mbn: fastboot flash modem modem.img fastboot flash fsg fsg.mbn.

Problem 2: Fast battery discharge after firmware

This is normal in the first 2-3 charge cycles, as the system calibrates the battery.

• 🔋 Reset the battery statistics to TWRP (Wipe → Battery Stats).
• 📉 Turn off the background activity of applications in Settings → Battery → Battery Optimization.
• 🔄 Install a kernel with optimized power management (e.g., FrancoKernel for Mi 9A).

Problem 3: Google Pay or banking apps are not working

On custom firmware or unlocked devices, banking applications often block work due to the lack of SafetyNet.

• 🔒 Install Magisk and Universal SafetyNet Fix.
• 📱 Hide root with MagiskHide Props Config (for Google Pay).
• 🔄 Return to the official MIUI and lock the bootloader.

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If you have lost your IMEI or serial number after you have gone through the firmware, restore it with the SN Write Tool (requires an authorized Xiaomi account and NV-data backup). Mismanipulation of the IMEI is illegal and can lead to the device being blocked by the operator!

7.Rollback to factory firmware

If the experiments with custom firmware failed, you can return the Mi 9A to the factory state in two ways:

1. Through Mi Flash Tool: Download the official firmware for your region and run it in Clean All and Lock mode. This will block the bootloader and return the warranty state (but will not restore the data).
2. Via EDL- Mode: If the phone doesn’t even include in the Fastboot, use Qualcomm EDL and the Mi Flash Pro utility. You will need an authorized Xiaomi account (authorization cost is ~$5).

For a complete reset to factory settings (if the phone is turned on):

1. Go to Settings → Additional → Recovery and Reset → Resetting.
2. In Recovery, select Wipe Data → Wipe All Data.

After the rollback:

• 🔄 Update your firmware to the latest version via MIUI Updater.
• 🔒 Enable bootloader lock (if you plan to sell the phone).
• 📱 Check all sensors and modules (camera, NFC, GPS).

FAQ: Frequent firmware questions Xiaomi Mi 9A