How to reflash Xiaomi Redmi 9C: official and custom firmware

Xiaomi Redmi 9C is a budget smartphone with good hardware, but standard MIUI firmware does not always suit users: someone wants to get rid of advertising, someone wants to get a fresh version of Android, and someone needs additional features through custom firmware. Firmware can solve these problems, but it requires accuracy: one wrong step – and the device will turn into a “brick”.

In this article, we will discuss all the ways to flash Redmi 9C (codename angelica): from official updates via MIUI Updater to install custom firmware via TWRP or Fastboot. Also, we will tell you how to avoid typical errors, where to download firmware and what to do if the phone does not turn on after the procedure. If you are a beginner, start with the official methods. Experienced users will find here detailed instructions for unlocking the bootloader and working with ADB.

Preparation for reflashing: what you need to know

Firmware is not just a system upgrade, it's a complete software replacement. Before you start, make sure that:

• 🔋 Battery charge at least 60% (preferably 80%) interruption due to discharge can "kill" the phone.
• 📱 The phone has unlocked the bootloader (if you're planning custom firmware). 9C it's locked in default.
• 💾 Backup of important data is done. The firmware erases internal memory (except for the microSD card).
• 🖥️ There's a Windows computer 10/11 or Linux (for Fastboot and Linux) ADB).

If you've never flashed Xiaomi, start with the official way through MIUI Updater. It's the safest and doesn't require unlocking the bootloader. LineageOS, Pixel Experience, gives you more freedom, but the risk of "bricking" is higher. Also remember, Xiaomi's warranty is removed when you unlock the bootloader or install unofficial software.

Official firmware through MIUI Updater

The easiest way to update your phone is through the built-in MIUI Updater app, which is suitable if:

• 📲 You want to stay on the official list. MIUI.
• 🔄 You need to upgrade to the latest stable version.
• 🔒 You don’t want to risk and unlock the bootloader.

Instructions:

1. Open Settings → About the phone → Software update.
2. Click on the three dots in the top right corner and select Select Service Pack.
3. If the update is available, download it (weight ~1.5-2.5 GB).
4. After downloading, click Reboot and Update.

The phone will restart and install the firmware automatically. Importantly, if the update hangs on the MI logo for longer than 10 minutes, don't panic - sometimes it takes up to 20 minutes. But if it's more than 30 minutes and the phone doesn't turn on, you'll have to use Fastboot (see next section).

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If the update is not available, check the region of the phone. In Settings → Additional → Region should be Russia or Global. To change the region, you may need to reset your settings.

Fastboot Firmware (official firmware)

If MIUI Updater doesn’t work or you need to “restore” your phone after a crash, use the firmware via Fastboot.

• 🔧 Restore the phone after “bricking».
• 📥 Installation of official firmware from scratch.
• 🔄 Downgraid (rollback) to an older version MIUI.

This will require:

• 💻 Computer with installed Xiaomi drivers and Mi Flash Tool.
• 📎 Cable USB Type-C (preferably original).
• 📦 Official firmware in.tgz or.zip format for Redmi 9C (codename).

You can download the firmware from the official Xiaomi website (choose the Stable version for Redmi 9C Global). Unpack the archive into a folder without Cyrillic characters (for example, C:\MiFlash\angelica).

Download Mi Flash Tool from Xiaomi|

Install ADB/Fastboot | drivers

Unpack the firmware to the root of the C:| disk

Disable the antivirus (it can block Mi Flash)|

Charge your phone to 80%|

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Step-by-step:

1. Turn off the phone. Press Power + Volume down to enter the Fastboot (Mi Bunny logo with Fastboot labeled).
2. Connect the phone to the computer.
3. Launch the Mi Flash Tool, press Select and specify the folder with the unpacked firmware.
4. At the bottom, choose Clean all (full cleaning) or Clean all and lock (clean + lock bootloader).
5. Press Flash and wait until it is finished (5-10 minutes).

⚠️ If the Mi Flash Tool is a bug, you can’t find fastboot:

• 🔌 Reconnect the cable to another USB-port USB 2.0).
• 🔄 Restart your computer and phone.
• 📥 Install drivers manually through Device Manager (look for Android Bootloader Interface).

Unlock the bootloader on the Redmi 9C

To install custom firmware (LineageOS, Pixel Experience, Havoc-OS) you need to unlock the bootloader. Xiaomi officially allows this, but the process takes up to 72 hours of waiting (due to security policy).

What you need:

• 📱 Mi Account Account Linked to Phone.
• 💻 Computer with ADB and Fastboot.
• 📎 The original cable. USB Type-C.
• 🔧 Mi Unlock Tool (download from the official website).

Instructions:

1. Turn on the phone to debug. USB and OEM-Unlocking: Go to Settings → The phone. → Version. MIUI and tap 7 times to activate Developer Mode. → Additionally. → For developers and include: Debugging by USB Unlocking OEM

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

Mi Unlock Tool

Mi Account

link the account to the device

At the end of the period, try again - the loader will unlock.

⚠️ Note: Once the bootloader is unlocked, the phone will automatically reset to factory settings. Xiaomi can also block unlocking if it is not ready:

• 📵 The phone was purchased less than 30 days ago.
• 🔄 You try to unlock more than once every 30 days.
• 🚫 Mi Account is not linked to your phone.

Installation of custom firmware (TWRP + Custom ROM)

Custom firmware gives a clean Android, no advertising in MIUI and additional features. However, for the Redmi 9C, the choice is limited due to the weak Helio G35 processor.

• 📱 LineageOS 18.1 (Android 11) – Minimalist interface, good optimization.
• 📱 Pixel Experience (Android 12) – design like Google Pixel, but can slow down.
• 📱 Havoc-OS – a lot of customization, but less stable.

The installation will require:

1. Unlocked boot loader (see previous section).
2. TWRP Castom Recovery for Redmi 9C
3. The firmware file is in.zip format.
4. Gapps (Google services, if they are not included in firmware).

You can download TWRP for angelica on the official website, and look for firmware on the XDA Developers or 4PDA forums (for example, here).

Installation instructions:

1. Download TWRP and firmware, transfer them to a microSD memory card.
2. Turn off the phone and press Power + Volume up to enter the Fastboot.
3. Connect your phone to your computer and execute the command: fastboot flash recovery twrp-3.7.0_9-0-angelica.img fastboot reboot recovery
4. The phone will reboot to TWRP. Make a backup (click Backup and select Boot, System, Data sections).
5. Click Wipe → Advanced Wipe and mark Dalvik, Cache, System, Data. Swipe for cleaning.
6. Go back to the main menu, press Install, and select the firmware file. Wait until it's finished.
7. If you need to, install Gapps (if they are not included in the firmware).
8. Reboot your phone (Reboot → System)

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The first download of custom firmware can take up to 15 minutes, and do not interrupt the process, even if the screen remains black for a long time.

Solving typical firmware errors

Even with the correct following of the instructions, errors can occur.

If the phone doesn’t turn on after a failed firmware, try:

1. Press Power + Loudness down for 20 seconds (hard reset).
2. Connect to your computer and check if the device is detected in Fastboot devices.
3. If the phone doesn’t respond, try flashing through EDL-Mode (requires an authorized Xiaomi account and a boxed Mi Authorized Account).

How to return the official MIUI after custom firmware

If custom firmware is unstable or you want to return the warranty, you can roll back to the official MIUI.

1. Download the official firmware for Redmi 9C in.tgz format (for example, from here).
2. Unpack the archive and launch the Mi Flash Tool.
3. Select Clean all and lock mode – this will return the stock Recovery and block the bootloader.
4. Connect your phone in Fastboot mode and press Flash.

Once the firmware is installed, the phone will automatically reset to factory settings and the bootloader will lock, and to re-install the custom firmware, you will have to re-unblock it (wait 72 hours).

⚠️ Note: If you sell your phone after custom firmware, be sure to return the official firmware MIUI. The buyer can check the status of the bootloader through fastboot oem device-info – if it is unlocked, this will reduce the cost of the device.

FAQ: Frequent questions about Redmi firmware 9C