How to flash Xiaomi Mi A1: official and custom firmware

Xiaomi Mi A1

Android One

“Brike” (inoperability) of the device due to a blocked bootloader or incompatible version of the software

In this guide, we will analyze all the stages of firmware - from preparing and unlocking the bootloader to installing official or custom software through Fastboot and TWRP. The emphasis is on current methods for 2026, taking into account the features of the Mi A1 (codename tissot). If you are a beginner, we recommend you to carefully study each section and not miss the warnings.

Preparation for firmware: what you need to know before you start

The Xiaomi Mi A1 firmware is not a complicated process, but it requires preparation. The main feature of this device is participation in the Android One program, which means:

• 🔓 The bootloader is officially unlocked through the Mi Unlock tool (unlike most Xiaomi devices, which require a wait of 72-360 hours).
• 📱 Absence MIUI: The firmware is based on pure Android, so custom ROMIt is easier to install, but the choice of official updates is limited.
• ⚠️ Warranty Loss Risk: Unlocking the bootloader will void the Xiaomi warranty even if you return the official software.

Before you start, check:

• 🔋 Battery charge of at least 60% (when discharged during firmware, the device may fail).
• 💻 Presence USB-Data-enabled cables (charging cables often don’t fit).
• 🖥️ Computer on Windows 7/10/11 (for Mi Unlock and ADB/Fastboot).

⚠️ Attention: If your Mi is yours A1 The bootloader can be locked at the hardware level, in which case unlocking is possible only through authorized Xiaomi service centers.

Also, back up your important data. The firmware erases:

• 📸 Photos and videos (storage in internal memory).
• 📱 Contact and SMS (If not synchronized with Google).
• 🎮 Application and game data (including saves).

Unlock the bootloader on Xiaomi Mi A1

Without an unlocked bootloader, it is impossible to install custom software or even official firmware through Fastboot. The procedure for the Mi A1 is simplified thanks to participation in Android One, but requires a binding Mi Account.

Step 1. Linking a Xiaomi account

1. Go to Settings → About Phone → MIUI version (yes, even on Android One this item is saved).
2. Click 7 times on the Build Number line to activate the developer mode.
3. Return to Settings → Additional → For developers and enable:

Connect the phone to your computer and confirm the debugging permission.

Step 2: Installation of Mi Unlock Tool

Download the latest version of the Mi Unlock Tool from Xiaomi's official website. Install the program and log in under the same account that you're linked to your phone.

Step 3. Unlocking

1. Turn off the Mi A1 and press Volume Down + Power to enter the Fastboot.
2. Connect your phone to your PC and start the Mi Unlock Tool.
3. Press Unlock – the process will take 10–30 seconds (no waiting, like on other Xiaomi devices!).

Step-by-step:

1. Unpack the firmware archive into a folder without Cyrillic characters (e.g., C:\MiA1\ROM\).
2. Install the Mi Flash Tool and run on behalf of the administrator.
3. Turn off your phone and log in to Fastboot (Loudness Down + Power).
4. Connect the device to your PC and in the Mi Flash Tool press Refresh – should appear COM-port.
5. Select the firmware folder and click Flash. From the bottom menu, select:

Wait for the end (5-10 minutes). The phone will reboot automatically.

If the process is 99% frozen or there is an anti rollback error, it means:

• 🔙 You are trying to install an older version of the software than the one that is already standing (forbidden by the Anti-Rollback mechanism).
• 🛠️ Solution: Find the new version of the firmware or reset the device via Fastboot with the command: fastboot erase userdata fastboot erase cache

💡

If the phone is stuck on the Xiaomi logo after firmware, press Volume Up + Power for 10 seconds to force a reboot. If it doesn't work, repeat the firmware with a full clean (clean all).

Installation of custom firmware through TWRP

To install custom ROM (LineageOS, Pixel Experience, etc.) will require custom recavers TWRP. the Official version for the Mi A1 is available on the TWRP website.

Step 1: Installation of TWRP

1. Download the latest version TWRP for tissot (file) twrp-3.7.0_9-0-tissot.img or newer).
2. Place the file in a folder with ADB/Fastboot (for example, C:\platform-tools\).
3. Turn on Fastboot on your phone and execute the command: fastboot flash recovery twrp-3.7.0_9-0-tissot.img
4. Immediately after installation, go to the recavers, holding Volume up + Power (otherwise the official firmware will overwrite TWRP!).

Step 2: Preparation for ROM installation

In TWRP, do:

1. Wipe → Advanced Wipe and mark: 🧹 Dalvik / ART Cache 🗃️ System 📄 Data 🧊 Cache

Wipe the selected sections (swipe to the right).

Go back to the main menu and connect the phone to the PC.

Step 3: Installation of firmware

1. Copy the archive with ROM and (if necessary) GApps (Google services) into internal memory.
2. In TWRP, select Install → specify firmware file → swipe for confirmation.
3. After installing the ROM, repeat the step for GApps (if needed).
4. Reboot to the system (Reboot → System).

⚠️ Note: If after installing custom firmware does not work camera module or fingerprint sensor, download a separate patch for Mi A1 (look XDA For "tissot camera fix" installed in the same way as GApps.

💡

Custom firmware on the Mi A1 often requires additional camera setup. Without a patch, the main camera can only work at 12 MP resolution (without HDR and portrait mode).

Addressing common mistakes

Even with the exact following of the instructions, there can be problems.

If the device does not respond to buttons and does not load (called hard brick), try:

1. Connect the phone to your PC and check if it is identified in Device Manager as Qualcomm HS-USB QDLoader 9008.
2. If yes, use the EDL Unbrick Tool to recover through emergency mode.
3. If not, take it to the service center (programmer required).

The official firmware (Android 9) is outdated and not recommended.