How to open the engineering menu on Xiaomi Mi 8: secret codes and features

Xiaomi Mi 8 – the flagship smartphone of 2018, which still remains relevant thanks to the powerful “iron” and flexible firmware MIUI. However, even experienced users do not always know that under the “hood” of the device is hidden engineering menu – a tool for fine-tuning hardware components, diagnosing faults and optimizing work. Unlike standard settings, this menu allows you to change the parameters that the manufacturer usually blocks: from adjusting the sensitivity of sensors to testing communication modules.

But why isn't this tool being advertised? Because careless changes to the engineering menu can lead to warranty loss, disruptions, or even bricking up of the device. Yet for advanced users and enthusiasts, this is a window of opportunity: you can manually adjust the camera, improve signal reception, test the battery, or even unlock the hidden functions of the Snapdragon 845 processor. In this guide, we'll discuss how to safely access the engineering menu on the Mi 8, what codes are used to do this, and what you can change in it - without risking turning a smartphone into a brick.

What is an Engineering Menu and Why You Need It

The Engineering Menu (or Engineer Mode) is a hidden partition of the Android operating system, designed for service centers and developers. It provides access to low-level settings of the hardware components of the smartphone, which are not available in the standard interface. MIUI. On the Xiaomi Mi 8, this menu is especially useful as the device features flagship modules that can be optimized:

• 📡 Network testing: signal strength check, choice of preferred network (2G/3G/4G), manual LTE.
• 🔋 Battery Diagnostics: Monitoring the Real State of the Battery, Calibration of the Charge Controller.
• 📸 Camera setup: adjusting autofocus, white balance, exposure settings (useful for photographers).
• 🔊 Audio tests: checking microphones, speakers, setting up the equalizer at the hardware level.
• 📱 Calibration of sensors: gyroscope, accelerometer, proximity sensor - they can be rechecked and reconfigured.

It's important to understand that the engineering menu is not a universal solution for all problems, for example, if your Mi 8 is not catching the network well because of a hardware malfunction of the antenna, then the software settings will not help here, but in cases where the problem lies in the wrong parameters of the communication module or the incorrect operation of the sensors, the engineering menu can be a salvation.

⚠️ Warning: Changing the parameters in the engineering menu without understanding their purpose can lead to unstable operation of the smartphone. LTE It can cause problems with connection to the network, and calibration of the battery with errors - to its rapid wear and tear.

Official and informal ways to open the engineering menu

There are several ways to activate the engineering menu on the Xiaomi Mi 8, but not all of them are equally safe. USSD, which work on most Xiaomi devices. unofficial ways (for example, through the use of ADB or third-party applications) may require unlocking the bootloader or root rights, which automatically deprives the warranty.

Consider both approaches:

For most users, the Mi 8 is the best solution. USSD-They don't require any more manipulation of the system and they work out of the box, but if you need advanced features (e.g. testing) IR-blaster or deep diagnosis NFC), We will have to consider alternative methods.

Step-by-step: how to open the engineering menu through USSD-code

The easiest and safest way is to use secret codes. The Xiaomi Mi 8 has several combinations, but the main one is ##4636#. It opens a menu with information about the phone, battery and usage statistics. However, a full-fledged engineering menu will require a different code.

Follow this instruction:

1. Open the standard Phone app (not messengers like WhatsApp or Telegram).
2. Enter the combination: ##36446337## This is a universal code for the engineering menu on Qualcomm Snapdragon processor devices (including the Mi 8).
3. A window will appear on the screen asking for confirmation of entry «OK» or».
4. If the code doesn’t work, try an alternative: ##4636## It will open the Testing menu, where some of the functions of the engineering menu are duplicated.

After successful entry, you will see the interface with tabs:

• Phone Information – Network Data, IMEI, signal.
• Battery Information - battery status, temperature, charge level.
• Usage Statistics – statistics of application usage.
• Wi-Fi Information – testing of the Wi-Fi module (on some firmware).

⚠️ Note: Some custom firmware (such as LineageOS or Pixel Experience) are standard USSD-The codes may not work. In this case, you'll need to use the codes. ADB Specialized applications such as Shortcut Master.

Extended Features: What You Can Configure in the Engineering Menu

The engineering menu on the Xiaomi Mi 8 offers dozens of options, but most of them are for professionals. We will highlight those features that can be useful to ordinary users - provided you understand the consequences of your actions.

1. Network and communications optimization

In the Phone Information section (or MTK Engineer Mode → Telephony, please:

• 📶 Select the type of network: to switch to LTE only, 3G only 2G only (useful in areas with unstable coating).
• 🔄 Reset network settings: if the smartphone is not registered in the network after the update.
• 📡 Test signal strength: check how well the Mi 8 catches your operator compared to other devices.

Battery diagnostics

The Battery Information tab shows:

• 🔋 Real battery capacity (in mAh) – if it is very different from the passport 3400 mAh, the battery is worn out.
• 🌡️ Battery temperature – critical for the Mi 8 starts at 45°C.
• 🔄 Charging status – here you can see why the smartphone is not charging (for example, due to a damaged cable).

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If you see Health: Poor in the battery section, it means that the battery is worn out by more than 50%, in which case it is recommended to replace it, as further use can lead to sudden shutdowns or battery bloating.

3. Camera setup

In the engineering menu there are hidden options for the camera module Mi 8 (basic 12 MPP, f/1.8 + telephoto 12 MPP, f/2.4):

• 📷 Calibration of autofocus: if the camera is long "catch" focus, here you can reset the settings or manually adjust the stepper motor.
• 🎛️ White Balance Adjustment: Useful for shooting in non-standard lighting (e.g. under incandescent lamps).
• 🔍 Sensor testing: check the ToF sensor (if you have one in your Mi 8 Explorer Edition).

4. Sensor testing

In the Sensors section, you can check:

• 🧭 Gyroscope and accelerometer – if games or applications VR work incorrectly.
• 👆 Approximate sensor – if the screen does not go out during the call.
• 💡 Light sensor – if the automatic brightness is malfunctioning.

Risks and Warnings: What Not to Do in the Engineering Menu

Despite its usefulness, the engineering menu is dangerous for inexperienced users, and setting errors can lead to:

• 🚫 Network loss: if you incorrectly configure the parameters of the communication module, the smartphone will cease to register in the operator’s network.
• 🔋 Rapid battery wear: Incorrect calibration of the charge controller can shorten battery life.
• 📱 Unstable system operation: changing the parameters of the processor or memory can cause constant restarts.
• 🔒 Loss of warranty: if the service center finds traces of interference in the engineering menu, repairs under warranty may be refused.

The following actions are especially dangerous:

• Change the NV-data settings (non-return network settings).
• Manual adjustment of battery voltage (Battery Voltage Offset).
• Disconnection of hardware components (e.g, NFC or IR-blaster).

⚠️ Note: On some versions MIUI (Especially global, access to the engineering menu may be limited, and if you see a message after you enter the code, "This function is disabled," it means that the manufacturer has blocked this feature. ADB ornamental.

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Before any changes to the engineering menu, back up your data through Settings. → Additionally. → Backup and reset, which will allow you to restore the system if something goes wrong.

Alternative methods: ADB and third-party applications

If USSD-The codes did not work, you can try to activate the engineering menu through Android Debug Bridge (ADB). This method requires connecting the smartphone to the computer and enabled debugging. USB.

Instructions for Xiaomi Mi 8:

1. Enable USB debugging in Settings → About Phone → MIUI version (click 7 times, then go back to Settings → Additional → For Developers).
2. Connect your smartphone to your PC and open the command line (or Terminal on macOS/Linux).
3. Enter the command to check the connection: Adb devices Make sure your Mi 8 appears in the list.
4. Start the Engineering Menu with Adb Shell Am Start -n com.android.settings/.DevelopmentSettings The first is the adb shell am start. -n com.android.settings/.TestingSettings

If ADB It seems too complicated, you can use third-party applications:

• MTK Engineering Mode – works on most Xiaomi devices, but requires root rights for full access.
• Shortcut Master – allows you to find hidden activity of the system, including the engineering menu.
• Xiaomi Secret Codes – collects all possible codes USSD-Xiaomi devices in one place.

However, remember: third-party apps may contain ads or malicious code, and download them only from trusted sources (such as APKMirror or the official developer’s website).

Frequent mistakes and their solution

When working with the engineering menu on Xiaomi Mi 8 users often face problems, let’s consider the most common ones and how to fix them.

If the Mi 8 has been manipulated in the engineering menu and has started to work unstablely (for example, spontaneously restart or shut down), follow the following steps:

1. Go to Safe Mode (hold the power button) → Reboot in Safe Mode).
2. Check if the problem persists. If it doesn't, it's the third-party app's fault.
3. If the problem remains, reset to factory settings (don’t forget to back up!).

FAQ: Answers to popular questions