Why do you need access to the engineering menu on the Redmi Note 4X?
The Xiaomi Redmi Note 4X is one of the most popular models of 2017, but even years later, its capabilities remain relevant to enthusiasts. The engineering menu (or Engineer Mode) is a hidden part of the system that the manufacturer leaves for diagnostics, testing hardware components and fine-tuning parameters that are not available in the standard MIUI interface.
This menu allows you to check the performance of sensors (accelometer, gyroscope, compass), calibrate the screen, test communication modules (Wi-Fi, Bluetooth, GPS), and change network settings — for example, force to switch to 4G-only or disable unused bands. However, it is important to understand that not all options are safe here. Misguided changes can lead to loss of communication, camera failures or even “bricking” of the device.
In this article, we will analyze all the working ways to log into the engineering menu for both versions of the Redmi Note 4X – with a Qualcomm Snapdragon 625 processor and MediaTek Helio X20, and also tell you which settings can be changed without risk, and which – only for experienced users.
Preparation: What to Know Before Entering Engineer Mode
Before you start, make sure your smartphone meets the following conditions:
- 📱 Model of the device: Xiaomi Redmi Note 4X (codename mido for Snapdragon or nikel for MediaTek. → The phone. → Model.
- 🔋 Battery charge: at least 50% Some tests (e.g., checking the communication module) can discharge the battery faster than usual.
- 📶 SIM card: if you plan to work with network settings, insert active SIM test.
- 🔄 Backup: Create a backup of important data through Settings → Additionally. → Backup. This is not necessary, but it is recommended for deep changes.
Also note that some firmware (especially custom ones) may block access to the engineering menu, and if nothing happens after you enter the code, your version of MIUI may have been modified.
⚠️ Warning: Changing the settings in the BandMode section may cause communication loss. If you are not sure about the actions, write down the current values before editing.
Method 1: Standard code for logging into the engineering menu
The easiest method is to use service code, which works on most Xiaomi smartphones, including the Redmi Note 4X, regardless of the version of the processor.
Open the Phone app and enter one of the combinations:
- 🔢 ##4636## is a universal code for Android, which will open a menu with information about the battery, usage statistics and tests.
- 🔢 ##36446337## - Alternative code for MediaTek (Helio version) X20).
- 🔢 ##4636## → press Menu (three dots) → Choose Engineer mode (MTK).
If nothing happens after entering the code, try the following:
- Make sure you enter the code accurately, without spaces.
- Use the standard Phone app, not third-party calls (like Truecaller).
- Restart the device and try again.
On the Qualcomm version, after entering the code, the Testing menu with limited functionality can open. №2.
☑️ Preparation for the Engineer Mode entrance
Method 2: Sign in via MTK Engineering Mode (for MediaTek)
If the standard code didn't work, and you have a version with a MediaTek Helio X20 processor, you can use a specialized application, which provides extended access to settings, including sensor tests and calibration.
Download the MTK Engineering Mode app from Google Play (or the official website if the Play Market is not available).
- Open the application and grant the rights of the Super User (if requested).
- In the main menu, select MTK Settings.
- Go to the Engineer Mode (MTK) section.
The application offers a convenient interface with categories:
| Section | Description | Risk of change |
|---|---|---|
| Hardware Testing | Tests of sensors, camera, speakers, vibrations | Low. |
| Connectivity | Settings Wi-Fi, Bluetooth, GPS | Medium. |
| Location | Calibration of GPS and motion sensors | Low. |
| Telephony | Network parameters (BandMode, LTE-ranges) | High-pitched |
⚠️ Attention: In the Telephony section → BandMode does not disable all bands at once, this will lead to a complete loss of communication, and you can only restore the settings through a reset or firmware.
💡
If the MTK Engineering Mode app doesn’t open the menu, try installing an older version (e.g. 2.0.5) – new releases may not support the Helio X20.
Method 3: Alternative method for Qualcomm (via ADB)
For the Redmi Note 4X version with Qualcomm Snapdragon 625 processor, standard codes often open a stripped-down menu. To get full access, you will need a PC connection and use ADB (Android Debug Bridge).
Instructions:
- Enable USB Debugging in Settings → About Phone → MIUI version (click 7 times, then go back to Additional → For Developers).
- Connect the phone to the PC and confirm the debugging permission.
- Open the command prompt (or Terminal on macOS/Linux) and type:
adb shell
am start -n com.android.settings/.DevelopmentSettingsIf this doesn’t work, try an alternative command to call the engineering menu:
adb shell am start -n com.qualcomm.qti.engineermode/.MainActivityThis method will open an extended menu with tests of the communication module, sensors and display, but beware: changing the parameters in the RF Band Selection section can disrupt LTE/3G.
What if the ADB does not recognize the device?
What settings can be changed safely?
Not all options in the engineering menu are equally useful, but here is a list of sections that you can explore without risking the device:
- 📊 Hardware Testing: Touch Screen Test - multi-touch and screen response test. Sensor Test - diagnostics of accelerometer, gyroscope, proximity sensor. LCD Test – search for broken pixels and check color rendering.
- 📡 Connectivity: Wi-Fi Test – check signal strength and connection speed. Bluetooth Test – test of data transfer between devices.
- 🔋 Battery Information: battery health, voltage and temperature data.
Here is what you should not touch without experience:
- ⚠️ Telephony → BandMode – Changing network bands can cause communication loss.
- ⚠️ NV Rebuild – resetting the parameters of the communication module (required for repair, but dangerous for beginners).
- ⚠️ Factory Reset – complete reset to factory settings (different from standard reset in the factory) MIUI).
💡
The most useful sections for the average user are Hardware Testing and Battery Information, and the rest of the settings are better not to change without a clear understanding of their purpose.
Frequent Mistakes and How to Avoid Them
When you're working with an engineering menu, you often have some of the most common problems, and here are the ways you can solve them:
| Problem. | Reason. | Decision |
|---|---|---|
| Code's not working. | Installed custom firmware or lock from the operator | Try alternative codes or use ADB. |
| Changes to the network signal have been lost. | All bands in BandMode are wrongly disabled | Return standard settings or reset through NV Rebuild |
| MTK Engineering Mode does not open the menu | Incompatible with Android version or processor | Install an old version of the application (e.g. 2.0.5) |
| Phone overheats on tests | Long-term load on the processor (e.g., GPU test) | Interrupt the test and let the device cool down. |
If after changes in the engineering menu, the smartphone began to work unstable (for example, stopped catching the network or the camera gives out artifacts), follow the following steps:
- Restart the device – sometimes it resets temporary errors.
- Go back to the engineering menu and check what parameters have been changed. Try to restore them manually.
- If the problem persists, reset your settings through Settings → Additional → Reset.
⚠️ Note: If the signal is missing after the BandMode changes and the standard reset does not help, the module may need to be firmware NVRAM through SP Flash Tool (for MediaTek) or QFil (for Qualcomm) is a complicated procedure, so you should contact the service center.