Reflashing Xiaomi Redmi 3S: from unlocking the bootloader to installing MIUI or custom software

Xiaomi Redmi 3S is the legendary budgetary 2016, which is still used by thousands of users. However, over time, official support for MIUI ends, and the stability of the work leaves much to be desired. Flashing the device can return to its former performance, add new features or even install the current version of Android. But the process requires care: a mistake at any stage can turn a smartphone into a brick.

In this guide, we will take a look at all the steps of Redmi 3S firmware, from tool preparation to MIUI installation or custom firmware like LineageOS or Pixel Experience, and focus on unlocking the bootloader, a key step that makes firmware impossible, and learn how to avoid common mistakes and what to do if something goes wrong.

Preparation for firmware: what you need to know before starting

Flashing isn't just an update through the settings menu, it's a complete software replacement that can both bring your Redmi 3S to life and bring it down. Before you get started, answer three key questions:

• 🔹 Why do you need it? Do you want to just update? MIUI Up to the latest version, install a clean Android or fix system errors?
• 🔹 Are you prepared for the risks? The firmware will void the warranty (if it is still valid), could lead to data loss or device failure.
• 🔹 Is there a backup? Without a backup of critical data (photos, contacts, messages), you can't start firmware.

If you are determined to continue, prepare the following:

• 📱 Smartphone Xiaomi Redmi 3S battery charge of at least 70% (better than 100%).
• 💻 Computer on Windows 7/10/11 (for Mac/Linux Additional drivers will be required).
• 🔌 Original. USB-cable (poor cables may interrupt the connection).
• 🔐 Mi Account tied to the device (required to unlock the bootloader).

⚠️ Attention: On Redmi 3S With a Qualcomm Snapdragon 430 processor, you can't flash custom software without first unlocking the bootloader. If you miss this step, the device will refuse to accept any firmware other than the official firmware. MIUI via Mi Flash Tool.

Step 1: Unlock the bootloader (Bootloader)

The bootloader on all Xiaomi smartphones is locked by default, a security measure that protects the device from unauthorized changes.To install custom firmware or even official MIUI through Fastboot, it must be unlocked.The process takes 3 to 15 days (depending on Xiaomi policy) and requires confirmation through the Mi Account.

Instructions for unlocking:

1. Activate Developer Modes: Go to Settings → About Phone. Tap 7 times on MIUI until the notification “You’ve become a developer” appears.
2. Link the device to your account: Return to Settings → Additionally. → For developers. Activate. OEM-unlocking and debugging USB. Connect your phone to your computer and confirm your debugging permission.
3. Run Mi Unlock Tool: Download the utility from Xiaomi's official website. Sign in with the same Mi Account as your phone. Follow the program's instructions. If you see a message that says "Wait X days," wait until the deadline.

⚠️ Note: If you are buying a Redmi 3S «hand, make sure the previous owner untie his Mi Account from the device, otherwise unlocking will not be possible without his participation.

Step 2: Selecting a firmware for Redmi 3S

Redmi 3S can be used in three types of firmware:

For most users, the best choice is the official global MIUI (V12.5.1.0 or later), which is devoid of most bugs and supports all the features of the device. If you want a pure Android, look for LineageOS 16 (Android 9) or Pixel Experience (Android 10).

Critical! The firmware for Redmi 3S and Redmi 3X (codenamed lando) is incompatible, despite the similarities, and installing the wrong software will lead to the phone's brook.

Download the firmware for the land model (Redmi) 3S)|Check the checksum (MD5) file|Unpack the archive in a folder without Cyrillic|Download the Mi Flash Tool (for Fastboot) or TWRP (for recovery)-->

Step 3: Install firmware via Fastboot (recommended method)

Fastboot is suitable for installing official MIUI and some custom firmware, and its advantage is reliability and minimal error risk.

• 🖥️ Computer with Qualcomm drivers installed.
• 📂 Firmware in.tgz or.zip format (for Mi Flash Tool).
• 🔧 The Mi Flash Tool.

Step-by-step:

1. Turn your phone into Fastboot mode: Turn off the device. Press Volume down + Power for 10 seconds. Connect to your computer, and a hare in a hat will appear on the screen.
2. Run Mi Flash Tool: Unpack the downloaded firmware into a folder. In the program, press Select and specify the path to the firmware folder. Select Clean all mode or Clean all and lock mode. + loader-lock).

⚠️ Note: If the Mi Flash Tool gives you an error can't receive hello packet, try it. USB-cable to another port (preferably) USB Disable the antivirus and firewall. Run the program on behalf of the administrator.

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If the phone is stuck on the MI logo after you've been firmwareed, don't panic. Turn it off with a long hold on the power button (20+ seconds), then turn it on again. If the problem recurs, repeat the firmware with a full clean (Clean all).

Step 4: Install custom firmware through TWRP

To install LineageOS, Pixel Experience or other custom firmware will require custom recovery – TWRP. This method is more flexible, but also more risky: an error in the choice of firmware or a poor quality file can lead to hard brick (irreplaceable breakage).

Instructions:

1. Install. TWRP: fastboot flash recovery twrp-3.6.2_land.img fastboot boot twrp-3.6.2_land.img Download the current version TWRP For land can be found on the official website.
2. Make a backup: In TWRP Select Backup. Mark Boot, System, Data. Save backup to SD-card.
3. Sweat custom firmware: Transfer the firmware file (.zip) to your phone. In TWRP, select Install → Select file → Swipe to confirm. After installation, run Wipe → Format Data (required!).

Important nuance: On Redmi 3S After installing custom firmware often stops working IR-blaster (infrared port) and NFC (If it was in your modification, it's because there's no driver in the unofficial builds.

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Custom firmware requires regular updates! keep an eye out for new releases on XDA or 4PDA forums to avoid security vulnerabilities.

Step 5: Solving Common Mistakes

Even with the correct instructions, there can be problems, and here are the most common mistakes and ways to correct them:

If your Redmi 3S does not respond to buttons and is not detected by a computer after a failed firmware, try EDL Emergency Mode.

1. Download the Mi Flash Tool and firmware for land.
2. Open the back cover of the phone and close the contacts Test Point (located next to the battery).
3. Connect. USB-Cable – The computer must identify the device as Qualcomm HS-USB QDLoader 9008.
4. Sweat through the Mi Flash Tool in Clean All mode.

⚠️ Attention: Test Point requires care. Incorrectly closing contacts can damage the motherboard.If you are not sure about your skills, contact the service center.

Step 6: Optimize the system after the firmware

After successful firmware, your Redmi 3S will run faster, but for maximum performance, follow a few additional steps:

• 🚀 Turn off animation: Activate for developers (as in step 1). Install Windows animation, transition animation and Animator Duration on 0.5x or shut it down completely.
• 🗑️ Remove unnecessary applications: With ADB or Titanium Backup remove bloatware (e.g. com.miui.analytics, com.xiaomi.midrop).
• 🔋 Optimize the battery: Turn off Auto Brightness and set a fixed value. Turn on Power Saving Mode in the battery settings.

If you have installed custom firmware based on Android 9-10, it is also recommended:

• 🎯 Use Magisk for root rights (installation through) TWRP).
• 🔒 Install MicroG instead of Google Services to save power.
• 📱 Calibrate the battery (discharge to 0%, charge to 100% without interruptions).

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To return the original camera settings (if the photo quality deteriorated after the firmware), install a modified Google Camera for the Snapdragon 430. 4PDA smack-in.

FAQ: Answers to Frequent Questions