How to enter the engineering menu on Xiaomi with MIUI 12: secret codes and features

Xiaomi’s MIUI 12-based smartphones hide a powerful diagnostic tool, the engineering menu, from users, which allows them to test hardware components, calibrate sensors, check battery status, and even change network settings that are not available in standard settings.

In this article, we will take a closer look at all the working methods of logging into the engineering menu on devices with MIUI 12, including hidden codes, key combinations and alternative methods through ADB. You will learn which parameters can be changed without risking damage to the system, and which settings are better not to touch, and we will also warn against common errors that can lead to malfunctions in the phone.

What is an Engineering Menu and Why You Need It

The Engineering Mode is a hidden partition of the Android operating system that provides low-level access to the hardware components of a smartphone. Unlike standard MIUI 12 settings, you can:

• 🔧 Test the performance of sensors (accelerometer, gyroscope, compass)
• 📶 Set up mobile network settings (frequency selection, priority) SIM-map)
• 🔋 Check the real state of the battery (voltage, current, wear and tear)
• 🎤 Calibrate microphone and speakers to improve sound
• 📡 Diagnose problems with Wi-Fi, Bluetooth and GPS

For example, if your Xiaomi is not catching the network well, you can manually select your preferred 4G/5G frequency through the engineering menu or turn off unstable ranges, and if you suspect a battery malfunction, you can display accurate data about its capacity and the number of charging cycles, information that standard applications do not show.

⚠️ Attention: Some of the options in the engineering menu can cause the phone to function unstable if changed without understanding the consequences. NFC It is able to completely disable contactless payments.

It is important to understand that MIUI 12 may restrict access to individual sections of the engineering menu on some models (especially the flagships of the Mi and Redmi Note series), this is due to Xiaomi’s policy to protect users from accidental changes that can disrupt the device.

Official ways to log into the engineering menu on MIUI 12

The most reliable method is to use service codes that run on most Xiaomi devices with MIUI 12 shells, which are universal and do not require root or additional application rights.

To use the code:

1. Open the Phone app.
2. Go to the Dialing tab.
3. Enter one of the codes (without spaces).
4. Press the call button and the menu will open automatically.

On some devices (e.g. Redmi Note 11 Pro+ 5G), code ##4636### may not work due to manufacturer restrictions.

Alternative Access Methods (without root)

If the standard codes do not work, you can use them. ADB-These methods require minimal preparation, but allow access to the same functions as service codes.

Method 1: ADB (Android Debug Bridge)

This method will require:

• 💻 A computer with installed Xiaomi drivers and ADB.
• 📱 Included debugging by USB on a smartphone (Settings) → The phone. → Version. MIUI — Press 7 times, then return to Additional → For developers).
• 🔌 USB Type C C Cable (Original or High Quality).

Instructions:

1. Connect your phone to your PC and open the command prompt (cmd on Windows or Terminal on macOS/Linux).
2. Enter the command to check the connection: adb devices If the device appears in the list, go further.
3. Execute the command to open the engineering menu: adb shell am start -n com.android.settings/.TestingSettings

After that, the Testing menu, which is the equivalent of the engineering section, will appear on the phone screen, and the same tabs are available here as when you use the codes.

Method 2: Apps from Google Play

There are apps in the Play Market that mimic access to the engineering menu, and the most reliable ones are:

• 🔧 MTK Engineering Mode – for devices running MediaTek processors (e.g. Redmi) 9A, POCO M3).
• 📱 Shortcut Master – Searches for hidden menus through system intent.
• 🛠️ Device Info HW — displays hardware information, partially duplicating the functions of the engineering menu.

⚠️ Note: Apps from third-party sources (not Google Play) may contain malicious code. APK-files from unknown sites, even if they promise to unlock all features".

What settings can be changed without risk

Not all the options on the engineering menu are equally safe, and here are some sections that you can explore without affecting your phone:

For example, in the Battery Information section you will see:

• 🔋 Battery Health – Battery status from Good to Replace soon).
• 📊 Charge cycles – the number of full charging cycles.
• ⚡ Voltage - current voltage (normal: 3.7–4.2V).

If the Battery health value shows Poor or Replace soon, it's a signal to replace the battery, even if the phone is holding a charge "normal." In standard MIUI 12 settings, this information is not available.

In the Sensors Test section, you can check:

• 🧲 Compass operation (useful for navigation applications).
• 🔄 Gyroscope – if the smartphone does not respond to turns in games.
• 👆 Approximation Sensor – responsible for turning off the screen during a call.

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If the proximity sensor doesn’t work, try clearing the area around the top speaker of dust and dirt – often this solves the problem without calibration.

Dangerous settings: what not to touch

Some options on the engineering menu can disrupt your phone or even cause you to lose warranty. Here is a list of sections that you can avoid:

• 🚫 Band Selection: Manual selection of mobile network frequencies, wrong settings can leave the phone without communication.
• 🚫 NV Rebuild - overwriting configuration files of the communication module.
• 🚫 RF Calibration is a calibration of a radio frequency module. It requires special equipment.
• 🚫 Hardware Testing → Auto Test – Automatic Testing can trigger irreversible processes.

The NV Rebuild section is especially dangerous, designed to restore network settings after a failure, but if used improperly, it can erase IMEI or Wi-Fi/Bluetooth data, which will result in the phone losing its ability to connect to networks, and recovery will require contacting a service center.

⚠️ Note: On devices with Qualcomm Snapdragon processors (for example, Xiaomi Mi 11, POCO F3) parameterization RF Calibration can cause signal loss GPS These settings are tied to a hardware configuration and are not designed to be manually edited.

If you accidentally change a critical parameter, try:

1. Reboot the phone.
2. Reset network settings in the standard menu (Settings) → SIM-maps and mobile networks → Resetting settings).
3. In the extreme, perform a hard reset (but it will delete all data).

How to exit the engineering menu and reset changes

To close the engineering menu, just press the Back or Home button, but some changes persist even after you exit. If you notice a problem (for example, a sound is lost or communication is deteriorating), follow the following steps:

Resetting of individual parameters

Most sections of the engineering menu have a Reset or Restore Defaults button, for example:

• In Network - reset mobile network settings.
• In Audio, the factory volume levels are restored.
• Sensors recalibrate sensors.

Complete reset of network settings

If the problems are connected to the connection (Wi-Fi, mobile Internet, Bluetooth), do:

1. Go to Settings. → SIM-maps and mobile networks.
2. Select Network Resetting.
3. Confirm the action and restart the phone.

This will return all network settings to factory values, including APN settings and connection priorities.

Hard Reset (full reset)

If the phone is unstable (hangs, overheats, discharges quickly), you may need a complete reset.

1. Turn off the device.
2. Press the Power button + Volume up until the Mi logo appears.
3. From the Recovery menu, select Wipe Data → Wipe All Data.
4. Confirm the action and wait for the process to be completed.

⚠️ Warning: Hard Reset deletes all data, including photos, contacts and installed apps. pre-backup through Settings → The phone. → Backup.

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If after the changes in the engineering menu, the phone stopped turning on, try going to Fastboot Mode (power button + volume down) and reflash the device through the Mi Flash Tool.

FAQ: Frequent questions about the engineering menu MIUI 12