Xiaomi Mi A3 firmware: official and custom methods with unlocking the bootloader

Xiaomi Mi A3 — One of the few smartphones of the brand, running on “pure” Android One instead of the proprietary shell MIUI. This gives users unique features for firmware, but also adds nuances: from the features of unlocking the bootloader to compatibility with custom recovery. A3 (codename laurel_sprout), including official updates, manual installation via Fastboot and TWRP, and the nuances of working with Android Flash Tool from Google.

It's important to understand that firmware is not only a way to upgrade your system, it's also a tool to restore your device to health after crashes, remove viruses, or even overclock performance. But the wrong actions can turn your smartphone into a brick. We'll go through each step in detail to minimize the risks, but remember, you do all the manipulations at your own risk.

Preparation for firmware: what to do before the start

Before you start firmware, you need to follow a number of mandatory steps, and neglecting them can lead to data loss, failures in the process, or even irreversible damage to the device.

First, back up all your data. The firmware (especially through Fastboot or custom recovery) erases internal memory. Use Settings → System → Backup to save contacts, messages and apps, and for media files, migrate to a PC or cloud. Note: backups created through MIUI (if you’ve been through it before) may not be restored on a pure Android One.

Second, check the current firmware version and the status of the bootloader:

• 📱 Android Version: Settings → The phone. → Android version. For Mi. A3 Official versions from Android 10 to Android 12 (last update from Google).
• 🔓 bootloader status: Turn off the phone, then hold power + Loudness down. If you see the word Device is locked, the bootloader is locked.
• 🔋 Battery charge: at least 60%. Firmware can take up to 30 minutes, and discharging in the process is fraught with failures.

Also prepare the tools:

• 💻 Windows PC 10/11 (for Fastboot or Linux/macOS (for ADB). Windows will require Xiaomi drivers USB Drivers and Google USB Drivers.
• 🔌 Cable USB (Cheap cables can cause data transmission errors.
• 📁 Firmware for your model. Download only from official sources: Xiaomi Firmware or Google OTA.

Unlock the bootloader on Xiaomi Mi A3

The bootloader on the Mi A3 is locked by default, a security measure from Xiaomi. To install custom firmware or even manually upgrade it through Fastboot, it must be unlocked. The process is different from the standard for devices on MIUI!

Step 1. Linking your Mi Account

Even on Android One, Xiaomi requires a binding to a Mi Account. Without this, unlocking is impossible.

• 📱 Xiaomi account added and confirmed on the phone (via Settings) → Accounts).
• 🌐 Account not new (registration less than 7 days ago blocks unlocking).
• 📧 Email confirmed and phone number tied.

Step 2: Requesting permission to unlock

Go to Mi Unlock and download the Mi Unlock Tool, launch it on your PC, log in with the same account you have on your phone, and follow the instructions.

• ⏳ After sending a request, you will have to wait 72-168 hours (3-7 days.
• 🔄 If you have previously unlocked the bootloader on another device, the wait can be reduced to 24 hours.

Step 3: Direct Unlocking

After receiving an SMS or permission notice:

1. Turn off the Mi A3 and press Power + Volume down to enter the Fastboot Mode.
2. Connect your phone to your PC and start the Mi Unlock Tool.
3. Press Unlock and wait until it is completed (usually 10-15 seconds).The phone will reboot with the bootloader unlocked.

1. Use another PC or Xiaomi account.

2. Enable debugging over USB in Settings → For developers.

3. Update the utility to the latest version.-->

Xiaomi Mi A3 firmware methods: which one to choose?

The choice of firmware method depends on your goals:

For most users, the best option is Fastboot (for clean installation) or OTA (for updates). Castom firmware through TWRP will suit advanced users, ready for possible bugs.

💡

If your goal is to simply upgrade to the latest version, start by checking. OTA-Updates to Settings → System system → Updating the system. It's the safest method.

Firmware through Fastboot: step-by-step instructions

Fastboot is suitable for installing official firmware (for example, when recovering from a crash) or changing the region.

Step 1: Download firmware and tools

• 📁 Download Fastboot firmware for Mi A3 (code laurel_sprout) Choose the version of Fastboot, not Recovery!
• 💾 Download the Mi Flash Tool (version 2020.3.14.0 or later).
• 🔧 Install Xiaomi drivers USB Drivers and Google USB Drivers (for Windows).

Step 2: Preparing the phone

1. Turn off the Mi A3.
2. Hold Power + Volume Down to enter Fastboot Mode (a hare in a hat-eared hat will appear).
3. Connect the phone to the PC.

Step 3: Firmware via Mi Flash Tool

1. Unpack the downloaded firmware (should be a file) flash_all.bat).
2. Run the Mi Flash Tool on behalf of the administrator.
3. Click Select and point the way to the firmware folder.
4. At the bottom, select Clean All (Full Cleaning) or Clean All and Lock (with bootloader Lock after Firmware).
5. Press Refresh – your device should appear in the list.
6. Click Flash and wait until it is completed (5-10 minutes).

The bootloader is unlocked|Battery charge > 60%|Xiaomi drivers installed|The correct version of the firmware has been downloaded (laurel_sprout)|Antivirus disabled (can block Mi Flash Tool)-->

⚠️ Note: If the Mi Flash Tool gives an anti-rollback error, it means that you are trying to install an older version of the firmware than the one already on your phone, in which case you need to flash an intermediate version (for example, first on Android 11, then on Android 10). You can download intermediate versions on the forums XDA Developers.

Installation of custom firmware through TWRP

Unofficial firmware installations (like LineageOS or Pixel Experience) require custom recovery TWRP. The process is more complicated than Fastboot, but provides more features.

Step 1: Installation of TWRP

Download the latest version of TWRP for Mi A3 from the official website.

1. Unpack the downloaded file twrp-3.x.x-x-laurel_sprout.img file ADB/Fastboot.
2. Enable USB Debugging in Settings → For Developers.
3. Connect your phone to your PC and execute the command: adb reboot bootloader
4. Install. TWRP Team: Fastboot Flash Recovery twrp-3.x.x-x-laurel_sprout.img
5. Recovery: Fastboot Reboot Recovery

Step 2: Firmware custom ROM

After installation of TWRP:

1. Download the firmware in.zip format (for example, with XDA).
2. Transfer the file to your phone or flash drive.
3. In TWRP, select Wipe → Advanced Wipe and select Dalvik, Cache, System, Data.
4. Return to the main menu, select Install and specify the path to the firmware.
5. After installation, run Gapps (if required) and Magisk (for root).
6. Reboot to the system.

⚠️ Note: Some custom firmware for Mi A3 have problems with the camera (no night mode) and NFC. Check the forum reviews before installing. Also note that after you have firmware customization ROM OTA-Updates will stop working – you will have to update manually.

Firmware via Google's Android Flash Tool

Android Flash Tool is Google’s official firmware tool for Android One devices, including the Mi A3. Its advantage is that you don’t need to unlock the bootloader (if you install the official firmware).

Step 1. Connecting the phone

1. Go to the Android Flash Tool website.
2. Turn on the phone debugging over USB and OEM-unlock (in Settings → For developers).
3. Connect the Mi A3 to your PC and allow debugging.

Step 2. Selecting firmware

The tool will automatically determine the phone model and offer available firmware. Select the desired version (such as Android 12) and press Install.

Step 3. Firmware

Follow the instructions on the screen. It takes 10 to 20 minutes, and when it's done, the phone will reboot with the new firmware.

1. Use the Chrome browser.

2. Disable the antivirus.

3. Reconnect. USB-cable.-->

Solving Firmware Errors

Even if you follow the instructions accurately, you can get errors, and let's look at the most common ones and how to fix them.

If after firmware the phone does not turn on or got stuck on the screensaver, try:

1. Keep Power + Volume up for 20-30 seconds for forced reboot.
2. If it doesn’t help, re-sweeten through Fastboot with a full cleanup.
3. For devices with unlocked bootloader: install TWRP and flash through it.

⚠️ Note: If you have a customized ROM Mobile networks have stopped working, check if the firmware supports your region. Some builds (for example, for the European market) do not work with Russian operators.

FAQ: Frequent questions about the firmware Xiaomi Mi A3