How to open the engineering menu on Xiaomi Redmi Note 4: all the ways and risks

Xiaomi Redmi Note 4 is one of the most popular smartphones of the brand, but even years after its release, its hidden features are of interest to enthusiasts. The engineering menu (or Engineer Mode) allows you to test hardware, calibrate sensors and even unlock hidden MIUI functions. However, not everyone knows that there are two types of engineering menus on this model – for MediaTek chips (the version of theo) and Qualcomm Snapdragon (the version of the nikel).

It's important to understand that the engineering menu is not for the average user. There are no beautiful icons here, only raw technical parameters, changing which can lead to loss of warranty, failure of modules or even "bricking" the device. But if you are willing to take risks for fine-tuning the antenna, checking the battery or testing the display - read on.

How the Engineering Menu is Different from the Developer Mode

Many people confuse the engineering menu with the developer mode (Developer Options), but these are fundamentally different tools:

  • 🔧 Developer Mode is an official Android feature that is enabled through settings. USB, Change animation or include a magazine HCI Bluetooth.
  • 🔬 The Engineering Menu is a hidden service interface, accessible through secret codes, and provides low-level access to hardware components: the module. NFC, gyroscope, radio modules and even memory tests.

For example, in developer mode, you can turn on OEM Unlocking to unlock the bootloader, and in the engineering menu, you can check the actual battery capacity or calibrate the compass. The latter option is much more dangerous: there is no protection against accidental changes.

📊 Why You Need an Engineering Menu?
For iron testing
To unlock hidden functions
Fixing communication problems
Just out of interest.
Another option

How to determine the version of the processor on Redmi Note 4

Before you enter the engineering menu, you need to know which chipset is installed in your Redmi Note 4, which not only depends on the login code, but also the available features.

  1. MediaTek Helio X20 (model mido) – common in Chinese and global versions.
  2. Qualcomm Snapdragon 625 (model nikel) - is less common, mainly in Indian firmware.

You can check the type of processor in three ways:

  • 📱 Through Settings. → The phone. → The kernel version, if the line mentions it. mt6797 — you have MediaTek; if msm8953 — Qualcomm.
  • 🔍 Using the application CPU-Z (subset).
  • 🛠️ Inscription on the box or under the battery (for disassembled devices).

💡

If in the Settings → There is no line "Kernel Version" about the phone, install the application AIDA64 — It will show the processor model in the CPU section.

How to log into the engineering menu for MediaTek (mido)

There are two working methods for the Helio X20 version: the first is through standard code, the second is using a third-party application (if the code does not work).

Method 1: Code #36446337##

This is the universal code for most devices on MediaTek.

  1. Open the Phone app.
  2. Enter the combination: ##36446337## (no spaces).
  3. The EngineerMode (MTK) menu will appear on the screen with tabs Telephony, Hardware Testing, Log and Debugging.

If the code is not working, check:

  • 📵 Are there any spaces or extra characters (code is case sensitive).
  • 🔄 Restart your phone and try again.
  • 🛡️ Disable ad blocking apps (such as AdGuard) that can intercept USSD-request.

Method 2: Application of MTK Engineering Mode

If the code doesn’t work (for example, because of custom firmware), install the MTK Engineering Mode app from Google Play. Once launched, it automatically determines the processor model and opens the menu.

Battery charge > 50% | Data backup | VPN and proxy disabled | Processor model tested-->

Sign-in methods for Qualcomm Snapdragon (nikel)

On the Snapdragon 625 versions, the standard MediaTek codes don't work, and it's using a different approach, through Qualcomm Diagnostic Mode.

Method 1: Code #4636##

This code opens the Android testing menu (not to be confused with the full engineering menu!) where:

  • 📊 Battery information (voltage, temperature, charge level).
  • 📡 Network usage statistics (including connection history).
  • 📱 Sensor data (accelerometer, gyroscope).

For a full-fledged engineering menu, additional software will be required.

Method 2: Shortcut Master Appendix

Install the Shortcut Master (Lite) from Google Play and follow the steps:

  1. Open the app and press Menu → Secret Code Explorer.
  2. In the list, look for Engineering Mode or Diagnostic.
  3. Create a shortcut on the main screen.
Why does #4636### not open the full engineering menu?
On Qualcomm chips, manufacturers often restrict access to low-level features through the use of a high-end chip. USSD-The full engineering menu is hidden deeper and requires either root rights or special commands. ADB. For example, to test a module NFC on the Redmi Note 4 Snapdragon may require a command: adb shell am start -n com.qualcomm.qti.engmode/.EngMode But this method does not work on all firmware. MIUI.

What to do in the Redmi Note 4 Engineering Menu

The functionality depends on the version of the processor, but in general, the engineering menu allows:

CategoryMediaTek (mido)Qualcomm (nikel)
📶 Communication testingManual LTE frequency setting, IMEI check, GSM/CDMA testView network information, but without manual settings
🔋 Battery.Checking the real capacity, calibration of the controllerOnly monitoring temperature and voltage
🎯 Sensors.Calibration of the gyroscope, accelerometer, compassTesting without calibration capability
🔊 Sound.Test speakers, microphones, setting up gainOnly the check of performance

For example, in MediaTek, you can manually select 4G frequency (useful in areas with poor coverage), and in Qualcomm you can only see the current network settings, but on Snapdragon you can access an advanced camera test, which is not available on the Helio X20.

💡

The most dangerous sections of the engineering menu are BandMode (frequency setting) and RF Test (radio module testing), changes here can lead to network loss or violation of the law (for example, if you turn on unlicensed frequencies).

Risks and warnings

The engineering menu is a tool for Xiaomi engineers, not end users. Here are the real consequences of careless action:

⚠️ Note: Change of settings in Telephony section → BandMode can cause you to lose your network login, for example, if you turn off all frequencies. LTE, smartphone will stop catching 4G, and restore the settings will be possible only through reset or firmware.

Other potential problems:

  • 🔄 Reset IMEI — if you accidentally erase the data in CDS Information, the phone will lose communication with the network.
  • 🔋 Incorrect battery calibration – can lead to sudden shutdowns or overheating.
  • 🎯 Sensor failure – after incorrect calibration of the gyroscope or compass of the application (for example, Google Maps or games) will not work correctly.

⚠️ Attention: On some firmware MIUI (especially global) access to the engineering menu is blocked at the kernel level. APK can lead to an anti-rollback trigger and complete loss of device performance.

Next Post: When an Engineering Menu Is Really Needed

Despite the risks, there are situations where you can't do without an engineering menu.

Case 1: Poor quality of communication in Redmi Note 4

If the smartphone does not catch the network well, in the engineering menu (MediaTek) you can:

  1. Go to Telephony → BandMode.
  2. Manually select the frequencies that work best in your region (e.g. B3 (1800 MHz) instead of B20 (800 MHz)).
  3. Check the signal level in Telephony → Signal Strength.

Case 2: Battery Authentication

If the battery is quickly discharged, you can use the Hardware Testing → Battery menu:

  • Find out the real capacity (in mAh) and compare with the declared.
  • Check the number of charging cycles.
  • See internal resistance (if it is above 200 mOhm, it is time to change the battery).

Case 3: Calibration of the proximity sensor

If the screen doesn't go out during the call, the reason could be a failure of the proximity sensor.

  1. Go to Hardware Testing → Sensor.
  2. Select the PS Sensor (Proximity Sensor).
  3. Press Calibration and follow the instructions (usually close the sensor with your hand and wait 5 seconds).

FAQ: Frequent questions about the Redmi Note engineering menu 4

Can I return the standard settings if I change something in the engineering menu?
Yes, but the way it works depends on the section: For BandMode, reset it with ##4636## → Network Reset. For sensors, reset the phone or reset it to factory settings. For IMEI, if it's erased, you can only restore it through Maui META (PC and cable required).
Why did the phone start to brake after entering the engineering menu?
You've probably activated logging in Log and Debugging, which puts a strain on the processor, to turn it off: Go back to EngineerMode → Log and Debugging, turn off all options that mention Log or Debug, restart the device.
Does the engineering menu work on custom firmware (like LineageOS)?
Most custom firmware doesn't work, as it's assembled without proprietary Xiaomi drivers. Exceptions: MIUI-based firmware with original modules saved (e.g. xiaomi.eu). Some AOSP builds, where the engineering menu is emulated through open libraries (feature limited). To check, type in code ##4636# — if it opens the menu, then there's a chance that other engineering functions are working.
Can I unlock the bootloader through the engineering menu?
No, the engineering menu is not about unlocking the bootloader. You need to: Get permission from Xiaomi through the official website. Use the Mi Unlock Tool utility. Connect the phone in Fastboot mode. The engineering menu does not provide access to fastboot or EDL.
Are there any alternatives to the engineering menu for diagnosis?
If you’re afraid to take risks, use these apps: AccuBattery for battery monitoring; Network Signal Guru for communication quality analysis; Sensor Box for sensor testing; MTK Droid Tools (MediaTek only) for backup of IMEI and NVRAM module.