Xiaomi Redmi 9 Engineering Menu: How to Open and What to Configure

The Xiaomi Redmi 9 is one of the most popular budget smartphones, but even it has features that most users do not realize about. The engineering menu (or Engineer Mode) is a hidden part of the system where you can test hardware, calibrate sensors and even change network settings.

In this article, you will learn how to safely log into the engineering menu on Redmi 9 (including Redmi modifications). 9A, 9C, 9T, 9 Pro and 9 Prime), what features are available there and what mistakes are most common for beginners.We will look at all the current ways - from standard codes to methods through the use of new technologies. ADB.

What is an Engineering Menu and Why You Need It

The Engineering Menu is an Android service section that manufacturers (including Xiaomi) hide from ordinary users.

• 🔧 Diagnostics of hardware components – screen checks, speakers, microphones, accelerometer and other sensors.
• 📡 Network settings - changes in parameters 4G/5G, Wi-Fi, Bluetooth (e.g. forced range selection) 2.4/5 GHz).
• 🔋 Battery testing – checking real capacity, charge/discharge current and temperature.
• 🎛️ Calibration of sensors - settings of a gyroscope, compass, proximity sensor.

However, not all features are available on Redmi 9 – some options are blocked by the manufacturer. For example, budget models often lack a section for manual 5G configuration (even if the chipset supports it), and some tests may give errors due to MIUI limitations.

⚠️ Warning: Changing the settings in the engineering menu can disrupt the stability of the smartphone, for example, incorrectly configuring Band Selection in the network section will lead to loss of connection with the operator.

How to log into the engineering menu on Redmi 9

There are three main ways to open the engineering menu on Xiaomi Redmi 9:

1. Through code - the easiest way, works on most firmware.
2. Settings are an alternative if the code doesn’t work.
3. ADB is for advanced users if the first two methods are blocked.

Let us examine each of them in detail.

Method 1: Using a secret code

This is the fastest way. You need to:

1. Open the phone application (call).
2. Enter the combination: ##4636## or #3644633###.
3. If the code worked, you will see a menu with tabs on phone information, battery usage, etc.

On Redmi 9 with MIUI 12/13/14, only the first code can work. The second (#3644633##) is more commonly used on devices with pure Android (such as POCO or Google Pixel).

Make sure that SIM-Card inserted (some codes require an active network)

Close all background applications

Connect charging (in case of long tests)

Make a backup copy of the data-->

Method 2: Through settings (if the code doesn't work)

If secret combinations don’t work, try this method:

1. Go to Settings. → The phone.
2. Click 5-7 times on the MIUI version until you become a developer!
3. Return to the main Settings menu and open Additional Settings → For developers.
4. Activate the developer mode switch.
5. Find the Local Engineering Menu (or Engineering Mode) option and click on it.

Some Redmi 9 firmware may not have this item, leaving only the ADB method.

Method 3: Through ADB (for advanced users)

If the first two methods don't work, you can use Android Debug Bridge (ADB), which requires a computer and a little preparation.

Instructions:

1. Download and install ADB Tools on PC.
2. Enable USB debugging on your smartphone (Settings → Developers).
3. Connect Redmi 9 to your computer via cable (use the original cord!).
4. Open the command line (Win + R → cmd) and type:

adb devices

If the device is determined, perform:

adb shell am start -n com.android.settings/.EngineeringMode

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

adb shell am start -a android.intent.action.MAIN -n com.miui.engineermode/.EngineerMode

⚠️ Note: On some versions MIUI (especially Global ROM) The engineering menu can be completely removed, and then you only have the firmware of the custom Recovery (e.g., the scaling-up menu, TWRP) for access to hidden functions.

Secret code.

Through settings

Through ADB

None of them worked.-->

What features are available in the Redmi 9 engineering menu

The interface of the engineering menu on Xiaomi Redmi 9 depends on the version of MIUI and the modification of the device. Below are the main sections that you will find there:

The Redmi 9 Pro and 9 Prime may have an additional Camera partition for manual focus, white balance and exposure, but on budget models (Redmi 9A/9C), these options are usually absent.

💡

If you only need to check the battery, use the code ##4636## → Battery Use tab, which shows the actual wear and tear level (in %) without risking damage to the system.

What can be set up and what can not be set up

Despite the wide range of options, not all settings can be safely changed.This is what is allowed and forbidden to do in the Redmi 9 engineering menu:

✅ What to do without risk

• 🔍 Check the state of the battery - voltage, current, temperature.
• 📱 Test sensors - gyroscope, accelerometer, light sensor.
• 📶 See network information - signal level, frequencies used.
• 🔊 Check the speakers and microphone for performance.

❌ What to do categorically can not be done

• 🚫 Changing Band Selection settings can result in loss of communication with the operator.
• 🚫 Calibrate the battery without special knowledge - incorrect values will lead to a quick discharge.
• 🚫 Change the parameters NV RAM — It can break down. IMEI.
• 🚫 Enable kernel debugging - the risk of system getting stuck.

For example, if you in the Telephony → Band Mode section disable all bands except LTE Band 20, and your operator does not support it, the smartphone will stop catching the network before resetting.

💡

The engineering menu is a diagnostic tool, not a smartphone overclocking tool, and most of the changes here won't improve performance, but they can easily make it worse.

Frequent Mistakes and How to Avoid Them

Many users make the same mistakes when working with the engineering menu.

1. Trying to change the IMEI is not only breaking the law, it is blocking the network forever.
2. Resetting settings NV RAM — This results in loss of network parameters, and the smartphone stops seeing. SIM-map.
3. Disabling important sensors (such as a gyroscope) – after that, some applications (such as games) will stop working.
4. Changes in battery voltage – can cause overheating or bloating of the battery.

If the Redmi 9 has stopped working normally after the changes to the engineering menu, try:

• 🔄 Reset network settings (Settings) → SIM-maps and mobile networks → Resetting network settings).
• 📱 Reset to factory settings (if the problem is serious).
• 🔧 Reflash the device through the Mi Flash Tool (at last).

⚠️ Note: If after changes in the engineering menu, the smartphone does not turn on or see SIM-map, don't try to solve the problem yourself - contact the service center. Notice that you climbed the engineering menu, not necessarily (this is not always visible in the logs).

Alternatives to the engineering menu for Redmi 9

If you need to test your smartphone but the engineering menu is not available, use these tools:

These apps are safer than the engineering menu because they don't allow you to make critical changes to the system, but they do provide less information -- for example, AccuBattery won't show the actual battery voltage, just the calculation data.

FAQ: Answers to Frequent Questions