How to open the engineering menu on Xiaomi Mi Max 3: secret codes and safe ways

Introduction: Why you need access to the engineering menu

The Xiaomi Mi Max 3, launched in 2018, is still popular with users thanks to its large screen, powerful battery and deep customization capabilities. One of the device’s most hidden yet powerful tools is the engineering menu, a special mode that allows you to test hardware, configure network settings, calibrate sensors and even unlock features not available in the standard MIUI interface.

However, logging into this menu is not as easy as it might seem. Depending on the firmware and chipset version (Qualcomm Snapdragon 636 or rare modifications with MediaTek), the ways of access may differ. Moreover, improper actions in the engineering menu can lead to loss of warranty, malfunctions or even “bricking” of the device. So before you start, it is important to understand why you need it and whether you are ready for potential risks.

In this article, we will discuss all working methods for entering the Mi Max 3 engineering menu, including secret codes, launcher applications and other applications. ADB-You'll also learn which settings you can change without harming your phone, and which you should not, and if your goal is to just test the display or the speakers, you'll have enough basic knowledge. But if you plan to overclock the processor or change the parameters of the communication module, be prepared for the consequences.

How to determine the chipset Xiaomi Mi Max 3

Before you try to enter the engineering menu, you need to know exactly which processor is installed in your device. This depends on the choice of code or method of entry. Xiaomi Mi Max 3 was released in two main versions:

  • 🔹 Qualcomm Snapdragon 636 – Most devices in the global and Chinese markets.
  • 🔹 MediaTek Helio P60/P70 — Rare modifications for some regions (e.g. India).

To find out the chipset model:

  1. Open the Settings app → The phone.
  2. Find the line CPU model or Hardware.
  3. If you don’t have any information, use the CPU-Z app (available on Google Play).
📊 What is the chipset of your Xiaomi Mi Max 3?
Qualcomm Snapdragon 636
MediaTek Helio P60/P70
I don't know, I haven't.
Other

Why does it matter? Qualcomm and MediaTek have different login codes, and if you type the wrong code, it's okay -- the system will just ignore the command, but knowing the chipset will save time and avoid unnecessary manipulation.

Method 1: Secret codes for Qualcomm

If your Mi Max 3 is powered by a Snapdragon 636 processor, use one of the following codes. They run on most MIUI firmware (including the global and Chinese versions):

Code.DescriptionWorks for MIUI.
##4636##Menu of Testing and Statistics (Basic Information)10–14
##6484##Testing of hardware (MTK Engineering Mode)9–12
##64663##Qualcomm Engineering Menu (full access)11–14
##225##Sensor calibration and camera test10–13

How to enter the code:

  1. Open the standard phone application.
  2. Go to the Set tab (where the number is entered).
  3. Enter the code without spaces and click on the call button.

Charge your phone at least 50 times%|Make a backup copy of important data|Make sure that SIM-map inserted (for network tests)|Record the current network settings (APN, IMSI)-->

What if the code doesn't work? Possible reasons:

  • 🔸 Outdated or modified firmware (e.g. custom LineageOS).
  • 🔸 The operator has blocked the engineering codes (rarely, but sometimes).
  • 🔸 There is a misprint in the code (check the characters * and #).

⚠️ Attention: On some firmware MIUI 13+ code ##64663## can cause a network reset. If the phone reboots after entering the code, check the settings of the Mobile Network - you may have to re-enter APN.

Method 2: Engineering menu for MediaTek-version

If your Mi Max 3 is running on MediaTek Helio P60/P70, Qualcomm's standard codes won't work.

  • 📱 ##36446337## - Main Engineering Menu MTK.
  • 📱 ##8255## - Test GPS sensory.
  • 📱 ##54298## — module Wi-Fi/Bluetooth.

Features of MediaTek-menu:

  • 🔧 The interface is less friendly – many items in Chinese or English with technical terms.
  • 🔧 There's an opportunity to change. IMEI (But it's illegal in most countries!).
  • 🔧 Advanced battery tests available, including real capacity.

Example of the MTK Engineering Menu screen:

MTK Engineer Mode




[1] Hardware Testing




[2] Network Setting




[3] Connectivity




[4] Location




[5] Others

⚠️ Attention: There is BandMode on the MediaTek menu, and if you change the frequency settings, you may lose communication with the operator. If you're not sure, don't change the settings!

Method 3: Log in via ADB (for power users)

If the secret codes don’t work (e.g., on custom firmware), you can use Android Debug Bridge (ADB), a method that requires a computer and basic command line knowledge.

Instructions:

  1. Install. ADB-drivers for Xiaomi (download from the official website).
  2. Enable USB Debugging in the developer settings (Settings → About Phone → MIUI version – press 7 times).
  3. Connect your phone to your PC and open the command line.
  4. Enter the command: adb shell am start -n com.android.settings/.DevelopmentSettings or direct access to the engineering menu: adb shell am start -n com.qualcomm.embms/.EngineerMode

If the team doesn’t work, try an alternative:

adb shell


su




setprop sys.usb.config diag,adb

💡

Before use ADB Check if the Allow Debugging option is enabled (USB-debugging) in the developer settings. Without that, commands won't be executed.

Critical information: On some firmware MIUI 14 with a blocked bootloader ADB-The commands to log into the engineering menu may not work without unlocking the bootloader, due to Xiaomi’s security policy aimed at combating unauthorized system changes.

What can be safely configured in the engineering menu

Not all of the options on the engineering menu are equally dangerous, but here is a list of features that can be tested without risk to the device:

  • 🔊 Test of speakers and microphone – checking the sound quality, sensitivity of the microphone.
  • 📱 Sensor calibration – if the screen does not respond well to touch.
  • 📶 Viewing network information – signal level, connection type (LTE/3G).
  • 🔋 Battery test – real capacity, temperature, charging cycles.

Example of safe actions:

  1. We're going to Hardware Testing. → Audio.
  2. Select LoudSpeaker Test and check both speakers.
  3. In Touch Screen we test multi-touch (simultaneous touch).

Here is what you should not change without deep knowledge:

  • 🚫 Band Selection – Manual selection of network frequencies (may cause loss of communication).
  • 🚫 NV Items – change of parameters of the communication module (risk of “bricking").
  • 🚫 Fast Dormancy – power saving settings (may impair connection stability).
What happens if you reset your network settings in the engineering menu?
Network Reset in the Engineering Menu removes all stored Wi-Fi hotspots, settings APN Bluetooth passwords, unlike standard resets in the MIUI, It also resets the parameters of the communication module, which can cause a temporary loss of signal. → SIM-Maps and mobile networks, but sometimes you need to restart your phone.

Risks and how to avoid them

The engineering menu is a tool for engineers and developers, not for ordinary users, and mistakes can have serious consequences:

Action.RiskHow to avoid
Change of IMEIIllegal, network blocking by the operatorDo not touch the CDS Information item
Resetting NV DataLoss of IMEI, "bricking"Create a backup with MTK Droid Tools
Changing BandModeLack of network or signal deteriorationRecord the current settings before changing

Basic safety rules:

  1. Do not change the parameters, the purpose of which you do not understand.
  2. Before any changes, make a backup via MIUI Backup or TWRP.
  3. If your phone is no longer catching the network, don't panic. Try resetting the network settings in the standard Settings menu. → SIM-map → Resetting network settings.

⚠️ Note: Some Xiaomi firmwares have their engineering menus changed in logs, and if the phone is warranty, it could cause a service denial.

💡

The engineering menu is not a toy. Even if you haven't changed anything, the login can be logged in to the system logs. If you plan to rent your phone under warranty, avoid using engineering codes 1-2 weeks before you visit the service center.

FAQ: Frequent questions about the Mi Max Engineering Menu 3

Can the processor be overclocked through the engineering menu?
Theoretically, yes, but on the Mi Max 3, it's extremely risky. There's a CPU Settings option on the Qualcomm menu, but changing frequencies without proper cooling will overheat and automatically shut down the phone. Moreover, MIUI has built-in limitations that won't allow much performance gains.
Why did the mobile Internet disappear after entering the engineering menu?
Chances are you accidentally changed your BandMode settings or reset NV Data. Try: Reboot the phone. Manually add APN operator in settings → SIM-map → Access points (APN). If it does not help, make a network reset in standard settings.
How do I get back to standard settings if I change something?
If you remember what settings you changed, return them to their original state. If not, try: Reset network settings (Settings) → SIM-map → Reset network settings. Perform factory reset (delete all data!) Refuse phone via Mi Flash Tool (require unlocked bootloader).
Does this code work on the Mi Max 3 with custom firmware?
On firmware like LineageOS or Pixel Experience, standard engineering codes don't usually work. ADB-method (section 3 of this article). Install the appendix MTK Engineering Mode (for MediaTek) or Qualcomm EngineerMode from Google Play. note that custom firmware may have a reduced or no engineering menu.
Can the speaker volume be increased through the engineering menu?
There are volume tests (Audio → Normal Mode) on the menu, but you can't change the maximum sound level - this is limited at the firmware level. Attempting to bypass the restrictions through the engineering menu can cause sound distortion or damage to the speakers. If you want higher volume, use third-party equalizer apps (for example, ViPER4Android).