How to enable developer mode on Xiaomi Redmi 3S: hidden features and secure settings

Xiaomi Redmi 3S — One of the most popular budget smartphones 2016 It's a year that's still used by thousands of users, despite its modest technical specifications. 430, 2/3 GB of RAM, the device supports advanced Android features through developer mode.This hidden partition allows you to unlock USB-Firmware debugging, speed up interface animation, debug applications and even improve performance on weak hardware.

However, many Redmi 3S owners face problems: the developer menu can suddenly disappear after the MIUI update, and some items (for example, OEM Unlock) are blocked by the manufacturer. In this article, the current instructions for all versions of the firmware (including MIUI 8-12), as well as a list of safe settings that will not damage the smartphone, we will analyze how to avoid typical errors (such as the lack of the “Build Number” item), and what to do if the mode turns off on its own.

Why you need a developer mode on Xiaomi Redmi 3S

By default, Xiaomi hides advanced settings to prevent accidental changes that could disrupt system stability, but for power users, the developer mode opens up the possibilities:

• 🔧 USB-Debugging: Connecting to a PC for firmware via Fastboot or ADB, Work with Mi Flash Tool.
• ⚡ Speed up the interface: disabling animation windows and transitions (relevant for weak Redmi) 3S with 2GB of RAM).
• 📱 Unlocking the bootloader: necessary for installing custom firmware (LineageOS, Pixel Experience).
• 🔄 Background Processes: Limiting the number of running applications to save battery.
• 🛠️ Error logs: access to system logs to diagnose problems (e.g. sudden reboots).

Redmi 3S features a special feature called “Don’t Turn Off the Screen While Charging” that allows you to use the device as a media player or navigator in the machine without locking the display. Developer mode also allows you to disable app signature verification, making it easier to install APKs from unknown sources (such as modified versions of YouTube Vanced or Spotify).

⚠️ Attention: MIUI 11+ Some of the developer menu items may be blocked by Xiaomi's policy. OEM Unlock is often unavailable without a Mi Account and waiting 7-30 days.

Preparation: check the version of MIUI and the Redmi 3S model

Before activating the developer mode, make sure your device meets the requirements. There are several modifications to Redmi 3S:

• 📱 Redmi 3S (codename land - standard version with 2/16 GB memory.
• 📱 Redmi 3S Prime (codename of land) — 3/32 GB memory and fingerprint sensor.
• 📱 Redmi 3X (codename lando - similar 3S Prime, but with a Snapdragon 435 processor.

To find out the exact model and version of MIUI:

1. Open the Settings. → The phone.
2. Scroll down to MIUI version (e.g. MIUI Global 12.0.3 Stable).
3. Click 5-7 times on the kernel version line and the code name of the model (land or lando) will appear.

On Redmi 3S with MIUI 12+, the “Build Number” item may not be in the “About Phone” menu, in which case use an alternative method (see Section 4).

Method 1: Standard activation via "Assembly Number"

This is a classic method that works on most versions of MIUI (except 12+).

1. Open the Settings. → The phone.
2. Find the MIUI version and click on it 7 times in a row.
3. You will be notified: You have become a developer.
4. Return to the main Settings menu – there will be a new section Additional → For developers.

If nothing happens after 7 clicks:

• 🔄 Reboot your smartphone and try again.
• 📱 Make sure you are clicking on the version. MIUI, Not the Android version.
• 🔧 Check if there are third-party launchers (like Nova Launcher) that can block system menus.

There is enough charge on the smartphone (minimum 30%)|A stable Internet connection is connected (to check for updates)|Disabled. VPN Proxies (can block access to Xiaomi servers)|Synchronized Mi Account data (to unlock) OEM)-->

Method 2: Alternative method for MIUI 12 and later

Starting with MIUI 12, Xiaomi hid the “Build Number” item in the About Phone menu, in which case use the roundabout through the diagnostic menu:

1. Open the Phone app and enter the combination: ##4636##.
2. You'll see a Test menu. Choose Phone Information.
3. Scroll down and press 7 times on the Build Number.
4. Return to Settings – The Developer section should appear in the Additional section.

If #4636### does not work,

• 🔧 Try entering ##284## (network testing menu).
• 📱 Install Activity Launcher from Google Play, search for Settings through it → DevelopmentSettings and Manually Launch.
• 🔄 Update. MIUI Up to the latest version – sometimes bugs with hidden menus are fixed in patches.

⚠️ Note: Some of the Redmi firmware 3S After activation of the developer mode, you may need to reboot the menu to appear in the settings. MIUI, repeat the activation procedure.

Developer Mode Settings: What You Can Change Without Risk

After activation, you will have access to dozens of options, but not all of them are safe for the Redmi 3S. Below is a list of settings that can be changed without the risk of “bricking” the device:

Dangerous settings that are not recommended to be changed to Redmi 3S:

• ❌ Turning off the absolute volume level can cause distortion of the sound.
• ❌ Secondary display imitation – causes artifacts on the screen.
• ❌ Forced shutdown of system applications – the risk of disrupting the work MIUI.

💡

If after changing the settings, the smartphone began to slow down, return the parameters Animation Scale and Background Processes to the default values and restart the device.

Unlocking OEM Unlock and USB-firmware

If you are planning to use Redmi 3S via Fastboot or install custom Recovery (TWRP), need to unlock OEM Unlock and turn on USB-But I'm not. MIUI This process is complicated:

1. Go to Settings → Additional → For developers.
2. Activate the switches: USB-debugging Unlocking OEM (It may not be available – see below)

Connect your smartphone to your PC and confirm the debugging permission.

If there is no OEM Unlocking:

• 🔧 Link your Mi Account to Settings → Xiaomi account.
• 📱 Go to the site. en.miui.com/unlock and request unlocking (waiting required) 7–30 days).
• 🔄 Update. MIUI Update - sometimes the item appears after the update.

⚠️ Attention: On Redmi 3S s MIUI 10+ unlocking the bootloader resets the device to factory settings. Backup the data through Settings → Additionally. → Backup.

Frequent problems and their solutions

Even after successful activation of the developer mode, Redmi 3S users are faced with typical errors:

If after changes in the developer mode, the smartphone began to overheat or discharge faster:

1. Return the parameters to the background processes and GPU-default acceleration.
2. Turn it off. USB-Debugging if you don’t use it constantly.
3. Check the temperature of the processor through the CPU Monitor app.

💡

On Redmi 3S with 2GB of RAM, it is not recommended to turn off background processes completely - this can lead to system services closure and unstable operation.

FAQ: Answers to Frequent Questions