How to Delete All Data from Xiaomi Redmi 9: From Reset to Deep Cleanup

Xiaomi Redmi 9 is a popular model with 4 GB of RAM and 64/128 GB of memory, but sooner or later the owner is faced with the question: how to properly delete personal data before selling, transferring or troubleshooting. Simply deleting files through the Explorer is not enough - residual information can be recovered by special programs. This article covers everything from a standard reset through the menu to forced cleaning through Fastboot and deleting the associated Mi Account.

The Redmi 9 feature (codenamed lancelot) is that it has Mi Cloud Lock protection, which locks the phone after a reset, unless you unplug the account in advance, and we'll look at how to avoid this problem, and we'll look at alternative ways to prevent the phone from turning on or locked. All instructions are relevant for MIUI 12/13/14 firmware based on Android 10/11.

1. Preparation for data deletion: what to do before resetting

Before you start cleaning, take critical steps to ensure you don’t lose access to your phone or data.

First, untie your Xiaomi account from your device. If you don't, the phone will require you to enter a username/password from the previous owner (Mi Account Lock protection). Check the binding in Settings → Xiaomi Account → Account Management. Delete the device from the list on account.xiaomi.com in the Devices section.

Second, keep backup copies:

• 📱 Contacts and Messages: Export through Settings → Google → Backup or Mi Mover application.
• 📷 Photo/video: copy to PC via USB-cable (enable File Transfer mode in notification curtain).
• 🔑 Wi-Fi passwords: write them down in advance – after resetting the network you will have to configure again.
• 🎮 Game saves: Use cloud services like Google Play Games or Mi Cloud.

⚠️ Note: If you sell a phone, deleting your Xiaomi account without uncoupling your device through a website will lock your phone after a reset, a common mistake that leads customers to return their gadgets.

Delete Xiaomi account from your device via settings | Untie your phone at account.xiaomi.com|Save IMEI (dial *#06#)|Copy files to PC/cloud |Write down passwords from Wi-Fi and apps-->

2. Standard reset via the settings menu

The easiest way is to use the built-in reset function, which is suitable if the phone turns on and you remember the pattern lock./PIN-code.

Instructions:

1. Open Settings → About Phone → Backup and Reset.
2. Select Resetting (on some firmware - Reset to factory).
3. Remove all data and confirm the action.
4. Wait for the reboot (it will take 3-5 minutes).

Once completed, the phone will start as new, with the screen of initial setup.

If the Reset option is not available (grey), then:

• 🔒 Parental control is installed on the phone - you need to enter the administrator password.
• 📱 The device is tied to corporate policy (for example, through Android Enterprise).
• 🔧 Debugging is on. USB with reset blocking (rarely, but occurs on custom firmwares).

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If the reset has been stuck on the Redmi logo for longer than 10 minutes, force the phone to restart by holding the power button for 15 seconds.

3. Reset via Recovery Mode (if the phone is not turned on)

When Redmi 9 doesn’t respond to clicks, is getting stuck or locked, Recovery will help.This method works even without a password, but does not delete Mi Account – the phone will remain tied to your account.

Step-by-step:

1. Turn off the phone (press the power button for 10 seconds).
2. Press Volume Up + Power and hold for 10-15 seconds until the Mi logo appears.
3. Release the buttons – you will be taken to the Recovery menu (navigation – volume buttons, choice – power button).
4. Select Wipe Data → Wipe All Data and confirm.
5. After cleaning, go back to the main menu and select Reboot → Reboot to System.

If the menu is in Chinese, focus on the icons:

• 🧹 Wipe Data - erasing data.
• 🔄 Reboot - reboot.
• 📱 Connect with MiAssistant – PC connection (no need).

⚠️ Note: Some Redmi 9 firmware in Recovery does not have Wipe All Data. In this case, use Fastboot (section 4).

Yes, on Xiaomi|Yes, on another phone|No, but I know it |No and I don't plan-->

4. Forced clean-up via Fastboot (for experienced)

Fastboot is the most radical method, which deletes all data, including system files, and requires a connection to a PC.

• 🔄 The phone is stuck in a reboot cycle (bootloop).
• 🔒 Forgot the pattern lock and Recovery is blocked.
• 📱 You need to reflash the device after a failed update.

What you need:

• 🖥️ Computer with Windows/Linux and installed drivers ADB/Fastboot.
• 🔌 Cable USB (preferably original).
• 📦 Firmware archive for Redmi 9 (download from official website).

Instructions:

1. Turn off the phone and press Volume Down + Power to enter the Fastboot (a hare in a hat-eared hat will appear).
2. Connect Redmi 9 to your PC and open the command line (Win + R → cmd).
3. Check the connection command: fastboot devices should appear serial number of the device.
4. Run full erase: fastboot erase userdata fastboot erase cache fastboot format:ext4 userdata fastboot format:ext4 cache
5. Reboot the phone: fastboot reboot

5. Delete the Mi Account after the reset (if you forgot to untie)

If you reset Redmi 9 without deleting your Mi Account, your phone will require you to enter your login/password when you first set up.

Method 1: Through the official website (if you remember the account details):

1. Go to account.xiaomi.com.
2. Log in and remove Redmi 9 from the device list in Device Management.
3. On your phone, link a new account or skip a step (if you sell).

Method 2: Through Support (if you don’t remember your password):

1. On the page of entering the password on the phone tap Forgot the password?
2. Select recovery via email/phone linked to your account.
3. If access is lost, contact Xiaomi with a purchase check and IMEI (see *#06#).

⚠️ Note: Mi Account unlock services are often fraudulent. Xiaomi does not provide official tools to bypass security – the only legal way is to restore access to your account.

6.Deep Cleanup: How to Delete Data Without Recovery

A standard reset does not guarantee complete deletion of files — you can restore them with programs like DiskDigger or Recuva.

Method 1: Repeated overwriting (for flash memory):

1. After reset, fill the phone’s memory with junk files (e.g., 4K video).
2. Remove them and repeat the reset.
3. Repeat 3-5 times, and this will reduce the chances of recovery to a minimum.

Method 2: Encryption + Reset (for power users):

1. Enable encryption in Settings → Security → Phone Encryption.
2. After the process is completed (it will take 1-2 hours), reset.
3. Encryption makes data unreadable without a key that is erased when reset.

Method 3: Use ADB (requires debugging over USB):

1. Connect your phone to your PC and enable USB Debugging in Settings → About Phone → MIUI version (tap 7 times according to version, then go back to Additional → For Developers).
2. In the command line, execute: adb shell su dd if=/dev/zero of=/dev/block/mmcblk0 Attention! This command will completely destroy all partitions, including system partitions. The phone will become a "brick" without firmware.

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For the sale of the phone is enough standard reset + detachment account Mi. Deep cleaning is necessary only when transferring confidential data (for example, corporate customers).

7. Frequent mistakes and how to avoid them

Error 1: “The phone asks for the old password after resetting”

• 🔹 Reason: Mi Account not untied or Factory Reset Protection enabled (FRP) Google.
• 🔹 Solution: Enter the details of an old Google account that was on the phone before the reset.

Error 2: “Reset is stuck on 99% or the MI logo”

• 🔹 Reason: Userdata partition is damaged or there is not enough space for temporary files.
• 🔹 Solution: Reset via Fastboot (Section 4) or connect your phone to charge and try again.

Error 3: "After reset, there is no network or sensors are not working"

• 🔹 Reason: Flew the firmware of the modem module or damaged drivers.
• 🔹 Solution: Sweat your phone with the official firmware through MiFlash (instructions on the Xiaomi website).

Error 4: “I can’t log in to Recovery or Fastboot”

• 🔹 Cause: Volume or power button is damaged.
• 🔹 Solution: Use ADB Recovery: Adb Reboot Recovery or Fastboot: Adb Reboot Bootloader

FAQ: Answers to Frequent Questions