How to upgrade or reflash Xiaomi Redmi 3S: full instructions with nuances

Why change firmware to Redmi 3S in 2026?

Xiaomi Redmi 3S (codenamed land) was released in 2016, but is still popular among users who value reliability and maintainability. However, over time, official support for MIUI for this model has ceased, and current applications require newer versions of Android.

First, custom firmware (like LineageOS or Pixel Experience) allows you to upgrade the Android version to 10-11, which increases compatibility with modern services. Second, it eliminates the built-in Xiaomi software that slows down the system. Finally, firmware helps restore the phone to work after software failures or viruses. But it is important to understand that the process requires accuracy - a mistake can turn a smartphone into a "brick".

This article is for beginners and experienced users alike, and we’ll go through all the steps from preparing and unlocking the bootloader to installing the firmware through Fastboot or TWRP Recovery, and find solutions to common bugs and tips for optimizing after the firmware.

1. Firmware Preparation: What to Do Before Starting

Before you start replacing your firmware, make sure that all the preliminary steps are followed. Failure to comply with at least one item can lead to data loss or device failure.

First, check the current version of MIUI and the status of the bootloader:

1. Go to Settings → About Phone → MIUI version.
2. Press the kernel (or Baseband) 5-7 times – the Fastboot menu will open (if the bootloader is unlocked, the Unlocked inscription will appear).

Next, prepare:

• 🔋 Battery charge at least 70%, firmware can take up to 30 minutes, and discharging in the process will cause a failure.
• 💾 Backup of all data (photos, contacts, SMS). Use Mi Cloud, Google Account or Adb Backup.
• 🖥️ Windows computer 10/11 (for Fastboot or Linux/macOS (for ADB).
• 🔌 Original. USB-Cheap cables don't have to transmit data in Fastboot mode.

⚠️ Attention: If your Redmi is 3S Purchased in China (Version with Prefix) CN in the model), firmware global version MIUI It can block the network. Check the frequencies you support before installing it!

2 Unlocking the bootloader: a mandatory step for custom firmware

Xiaomi’s bootloader is locked by default, and unlocking it is a must for unofficial software installation.The process takes up to 72 hours due to Xiaomi’s security policy, so start with it in advance.

Instructions for unlocking:

1. Download the Mi Unlock Tool (the official tool from Xiaomi).
2. Sign in to Mi Account on your phone and in the program on PC (should be one account!).
3. Put your phone in Fastboot mode: Turn off the device, then press Volume Down + Power.
4. Connect your phone to your PC and launch the Mi Unlock Tool. Press Unlock.

The system may give you a "Couldn't unlock" error, which means you have to wait. Check status once every 24 hours. Once you successfully unlock it, the phone will display a warning "This device is unlocked."

💡

If the Mi Unlock Tool doesn’t see the device, try disabling the driver signature check in Windows. To do this, reboot the PC with the Shift key pressed, select Diagnostic → Additional settings → Boot options → Reboot, then press F7 (disable verification).

3. firmware selection: official MIUI vs custom builds

Redmi 3S has two types of firmware: official (from Xiaomi) and custom (from the community), each with pros and cons.

Official MIUI firmware:

• ✅ Stable operation of all functions (camera, sensors, mobile network).
• ✅ Support OTA-update.
• ❌ Outdated version of Android (maximum 7.1 Nougat).
• ❌ Advertising and unnecessary applications.

Castom firmware (LineageOS, Pixel Experience, HavocOS)

• ✅ Android 10–11 with modern features.
• ✅ No advertising and no bloat.
• ❌ Camera or Wi-Fi bugs are possible (depending on build).
• ❌ No. OTA-Updates (must be re-flashed manually).

For beginners, we recommend starting with the official global firmware (e.g. MIUI 11 for land).Saved users can try LineageOS 17.1 (Android 10) or Pixel Experience for pure Android.

4. Install firmware via Fastboot (recommended method)

Fastboot is suitable for installing official MIUI firmware and some custom ones (if they support.tgz format) and is considered more reliable than Recovery, as it flashes all partitions, including boot and modem.

Step-by-step:

1. Download ADB & Fastboot Tools and unpack it into the C:\platform-tools folder.
2. Download the firmware in.tgz format (for example, land_global_images_V11.0.2.0.NALMIXM_20200310.0000.00_7.1_global_4a9b4a4b.tgz) And unpack it in the same folder.
3. Turn your phone into Fastboot mode (Loudness down + Power).
4. Connect your phone to your PC and open the Command Prompt in the platform-tools folder (click Shift + PCM → Open the PowerShell window here).
5. Run the command to check the connection: fastboot devices should appear serial number of the device.
6. Run the firmware: fastboot flash all (if the firmware file is called otherwise, specify its name, for example: fastboot flash all). land_global_images.tgz).

It takes 5-10 minutes. When it's done, the phone automatically restarts. The first run after the firmware can take up to 15 minutes -- don't interrupt it!

⚠️ Note: If your phone is stuck on the Mi logo after being firmwareed through Fastboot, then the firmware is not suitable for your model. TWRP.

5. Install custom firmware through TWRP Recovery

To install LineageOS, Pixel Experience or other custom firmware, you will need TWRP Recovery, an alternative recovery menu, and you will need to stitch it separately.

Steps to install TWRP and custom firmware:

1. Download. TWRP for Redmi 3S (file twrp-3.6.2_9-0-land.img).
2. Fastboot: Fastboot Flash Recovery twrp-3.6.2_9-0-land.img
3. Without turning off your phone, go to TWRP: Press Volume Up + Power.
4. In TWRP, make a full backup (click Backup and select all partitions).
5. Wipe the Dalvik, Cache, System, Data sections (Wipe → Advanced Wipe button).
6. Install firmware: Install → choose ZIP-file → Swipe to Confirm Flash.
7. Once you install the firmware, be sure to flash Gapps (if they are not included in the build). Download the appropriate package (for example, OpenGapps nano for Android 10) and install similarly.

If there is no mobile network after the reboot, check the APN settings or install a patch for the modem (look for 4PDA in your firmware theme).

💡

Installing via TWRP allows for selectively stitching components (such as only the kernel or modem), but requires more knowledge. For beginners, it is safer to use the Fastboot method.

6. Solving errors after firmware

Even with the correct following of the instructions, problems can arise. Let's look at the typical errors and how to fix them.

If the phone doesn’t respond to buttons, try a hardware reset:

1. Turn off the device (clip the power for 10 seconds).
2. Press Volume Up + Power for 15 seconds – the phone should reboot in Recovery.
3. Choose Wipe Data → Factory Reset.

7. Post-Firmware Optimization: How to Speed Up Redmi 3S

Once you've successfully firmware, you can further improve the performance of the device, and here are some proven ways to do this:

• 🚀 Turn off animation: go to Settings → About the phone, tap 5 times on the build number, then in the developer settings set Windows animation = 0.5x.
• 🔄 Use lightweight launchers: Nova Launcher or Lawnchair consume less memory than standard launchers MIUI Launcher.
• 🗑️ Clean the cache regularly: in Settings → Memory. → Cleaning or through SD Maid.
• 🔋 Limit background processes: In Developer Settings, set a Process Limit = Maximum 2 of the process.

For custom firmware on Android 10+, we recommend:

• Install Magisk for root rights and optimization modules (e.g. Universal GMS Doze for battery saving).
• Use Greenify to hibernate unnecessary applications.
• Shut down. ADB-After the scoring, it will be recharged).

If the battery is discharged quickly after firmware, calibrate it:

1. Charge your phone to 100% and don’t turn off charging for another 1 hour.
2. Turn off and discharge until automatically turned off.
3. Repeat the cycle 2-3 times.

FAQ: Frequent questions about Redmi firmware 3S