Xiaomi Redmi Note 9 is one of the most popular smartphones in the budget segment, but even it sometimes has sensors knocked down. Especially often users face the problem of incorrect compass operation: the arrow twitches, shows the wrong direction or refuses to determine the directions of the world. The reasons can be different from software failures to magnetic interference. In this article, we will analyze all the ways of calibrating the compass on the Redmi Note 9, including hidden settings and workarounds for complex cases.
You will learn how to check the sensor performance, perform manual and automatic calibration, and what to do if the compass never worked. This material is relevant for all versions of the Redmi Note 9 (including the Pro and Pro Max) based on MIUI 12-14 and Android 10-13. For convenience, we added interactive checklists, warnings about typical errors and a table with code commands for diagnosis.
Why is the compass on the Redmi Note 9 wrong?
Before you start calibrating, it's important to understand the root of the problem, because the compass in a smartphone is not a single sensor, but the work of a magnetometer, accelerometer, and gyroscope, and if any of them fails, the compass needle will lie.
- 🧲 Magnetic interference: metal covers, magnets, electronics nearby (e.g. wireless headphones or powerbank).
- 📱 Software failure: after the update MIUI or resetting sensors may require recalibration.
- 🔄 Incorrect initial setting: if the first time you turn on your smartphone, you missed the calibration stage of the sensors.
- 🛠️ Physical damage: falls or impacts can displace the magnetometer inside the enclosure.
- 📡 Problems with GPS: The compass is often synchronized with satellite data, and if GPS glitch, suffer accuracy.
Interesting fact: Redmi Note 9 uses a magnetometer AK09918 company AKM, If you've recently brought your phone from cold to heat (or vice versa), the sensor may temporarily malfunction, so you just have to wait 10-15 minutes before the temperature levels out.
⚠️ Warning: If the compass stopped working after a smartphone drop or moisture hit, calibration will not help, in this case, a diagnosis is required at the service center - perhaps the sensor contacts have moved away or the board has corroded.
How to check the compass before calibration
Before you set up the sensor, make sure it's the problem.
- Open the Compass app (standard or third-party, such as Compass Galaxy).
- Place the phone on a flat surface and rotate it 360°. The arrow should follow the movement smoothly.
- Compare the readings with a physical compass or Google maps (enable Compass Mode in navigation).
If the arrow twitches, freezes or shows direction with an error of more than 20-30°, The sensor needs calibration, and check the other sensors:
- 📲 Accelerometer: Open the Sensor Test app (available on Google Play) and check for tilt response.
- 🌀 Gyroscope: in the same application, spin the phone - the values should change smoothly.
If the accelerometer or gyroscope is not working properly, calibration of the compass may not work, in which case, first perform the reset of the sensors through the engineering menu (we will discuss this below).
Method 1: Automatic calibration via MIUI settings
The easiest method is to use the built-in calibration function in MIUI, which is available on all firmware versions, but the path to it may vary.
Instructions:
- Open the Settings. → The phone.
- Tap 5-7 times on the MIUI version until you become a developer!
- Return to the main settings menu and select Additional → For developers.
- Find the item Calibration of the compass (or Sensors → Calibration of the magnetometer in new versions).
- Follow the instructions on the screen: usually you need to rotate the phone in the air on the figure of "eight" 2-3 times.
Once you're done, check the compass accuracy. If the arrow is still swimming, proceed to manual calibration.
Make sure there are no metal objects nearby.
Remove the cover (especially with magnetic fastening)
Close all applications that use GPS
Turn on "In the plane" mode for 10 seconds, then turn off-->
⚠️ Note: Do not calibrate in areas with a strong electromagnetic field (such as near a microwave, refrigerator or Wi-Fi router) this can exacerbate the problem.
Method 2: Manual calibration through an engineering menu
If the automatic method didn't work, try manually adjusting through the engineering menu, which is more accurate, but requires caution - wrong actions can bring down other settings.
Steps:
- Open the Phone app and type the combination: ##6484## (some firmware may run ##4636## → Testing → Sensors).
- In the menu that opens, select the Magnetic Sensor.
- Press Calibrate and follow the instructions: you usually need to rotate the phone in different planes.
- After calibration, check the values of X, Y, Z – they should change when the phone moves.
If there is no calibration item in the engineering menu, try the alternative code:
##64663##It opens the MTK test menu (if your Redmi Note 9 is on a MediaTek processor).
| Code. | Appointment | Note |
|---|---|---|
| ##6484## | Sensor test (accelerometer, gyroscope, magnetometer) | It works on most versions of MIUI. |
| ##4636## | General testing (includes sensors) | Choose Testing → Sensors → |
| ##64663## | MTK Engineering Menu | Smartphones only on the MediaTek Helio G85 |
| ##36446337## | Sensor information | Shows raw data from the magnetometer |
💡
If after entering the code nothing happens, try dialing it in the application "Phone" without SIM-Some operators block engineering commands.
Method 3: Calibration through third-party applications
If standard methods don't work, use specialized utilities, which often offer more flexible customization and visualization of the process.
Top.-3 Applications for compass calibration on Redmi Note 9:
- 📱 GPS Status & Toolbox: shows the status of satellites and allows you to calibrate the magnetometer manually.
- 🧭 Compass Galaxy: has a built-in calibration wizard with motion animation.
- 🔧 Sensor Test: Tests all sensors and suggests resetting them.
Example of calibration using GPS Status:
- Open the app and go to the Compass tab.
- Press Calibrate and follow the prompts (usually describe a circle in the air with your phone).
- After completion, check the readings: if the arrow is stable, the calibration was successful.
The advantage of third-party apps is that they often show raw data from sensors, which helps diagnose the problem, for example, if the values of X, Y, Z do not change when the phone moves, the sensor is faulty.
What to do if the application does not see the magnetometer?
What to do if the compass doesn’t work anyway?
If none of these things work, the problem may be deeper. Here are the alternatives.
- 🔄 Reset sensor settings: In the engineering menu (#6484##) select Clear Calibration (if any).
- 📲 Update MIUI: Sometimes sensor bugs are fixed in new firmware versions. Check the updates in Settings → The phone. → Updating the system.
- 🛠️ Flashing: If the crash occurred after the update, try rolling back to the previous version MIUI via Fastboot.
- 🔧 Replacement of sensor: In the service center, you can replace the magnetometer (cost) ~1500–2500 ₽).
Critical information: On the Redmi Note 9 (model M2003J15SC), the magnetometer is soldered to the motherboard. Its replacement requires soldering, so unofficial services may refuse to take up repairs.
If you suspect a hardware malfunction, run a quick test:
- Turn on Airplane Mode.
- Open the Compass Galaxy and look at the arrow.
- If it still twitches or does not respond to corners, the sensor is faulty.
💡
Before you visit the service center, back up your data. Resetting to factory settings or flashing it will remove all the information from your phone!
How to Care for a Compass to Avoid Problems in the Future
To make the compass on the Redmi Note 9 work steadily, follow the following simple rules:
- 📵 Avoid metal covers, especially those with magnetic fasteners.
- 🔋 Do not use wireless charging while navigating – the magnetic field of the coil knocks the sensor down.
- 🌡️ Let your phone adjust to the temperature if brought from the street in the winter.
- 🔄 Periodically check the accuracy of the compass (every 2-3 months) through the application GPS Status.
- 📲 Do not drop the phone - blows most often disable it is the magnetometer.
It’s also helpful to know that the compass calibrates automatically when you first turn on your GPS in new places. If you travel frequently, give your smartphone 1-2 minutes to “get used” to a new location before using your navigator.
Interesting life hack: if the compass starts to glittle after installing a new application (for example, playing with AR), try to disable its access to sensors in the settings of the Application → Resolutions. Some programs conflict with system services.