How to find out the real state of the Xiaomi phone: from the battery to the processor

Are you planning to buy a used Xiaomi or just want to assess the current state of your smartphone? Unlike new devices where the warranty covers hidden defects, used phones require careful inspection. Even the seemingly perfect Redmi Note 12 or POCO X5 can hide problems with the battery, overheating processor or "killed" drive. In this article, 7 proven diagnostic methods that are used by service centers and experienced users.

We will analyze not only standard tests through Settings → About the phone, but also hidden engineering menus, ADB commands, as well as third-party utilities that will show the real wear of the battery (including the number of charging cycles) and the performance of the chipset. We will pay special attention to the typical “diseases” of Xiaomi: battery capacity degradation after 500 cycles, problems with NFC in budget models and overheating of the Snapdragon 7xx under long loads.

1. Check through the standard menu "About the phone"

Start with basic information, which will give you the first signals of potential problems. Open Settings → About the phone and pay attention to:

• 🔋 Screen time (if less than 3-4 hours at 100% charge - the battery is worn out)
• 📱 Model of the device (check with the box - fakes are common) POCO under-the-redmi)
• 🔄 Version. MIUI (Older firmware can hide hardware defects)
• 📊 Total memory (if less than the declared - there may be problems with the drive)

Please note the battery status (available on the MIUI 13+). If it says "Good" or "Normal", but the phone runs out in 2-3 hours - the data is falsified (often found after replacing the battery in informal services). №3 using ADB.

2. Hidden engineering menu: ##4636##

This menu is hidden from the general public, but contains critical data on the condition of iron.

##4636##

After entering, a menu with tabs will open:

• 📊 Phone information – check Outtime here (if it resets when rebooting – motherboard issues).
• 🔋 Battery information – key parameters: Charge level (should match the indicator in the status bar) Temperature (above 40)°C at simple - a sign of degradation) Voltage (normal: 3.7–4.2V; below 3.5V — wear-and-tear)
• 📡 Usage statistics – will show which applications load the processor in the background.

⚠️ Note: If the code is entered after the code is entered, the message "Code is not supported" appears, then:

⚠️ Your device has custom firmware installed (like LineageOS) that blocks access to the engineering menu. ADB (method №3) or utility like AccuBattery.

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Take a picture of the screen with the data from the engineering menu before buying a used phone – this will help prove the seller’s deception, if it turns out later that the battery was worn out.

3. ADB-deep-diagnostics

Tool. ADB (Android Debug Bridge allows you to get data that is not available through a standard interface, such as the actual number of battery charging cycles or the state of the device. eMMC/UFS-Here's how to do it:

1. Install Platform Tools on your PC.
2. Turn on the phone to debug by USB (Settings → About Phone → MIUI version – tap 7 times, then go back to Additional settings → For developers).
3. Connect the phone to the PC and type in the command line:

adb shell


dumpsys battery

In the conclusion, find the lines:

• Health - must be 2 (good condition). 3 or 4 means critical wear.
• charge counter – shows the real capacity in mAh (compare with passport).
• Temperature: If above 45°C, the battery needs to be replaced.

To check the drive, use:

adb shell


df -h

Note the Use% column – if it’s close to 100% on the /data partition, it’s a sign of cache cache or file system issues.

Install Platform Tools on PC

Enable debugging over USB on your phone

Connect your phone to the original cable

Start the command line on behalf of the administrator

Check the connection of the adb device team-->

4. Battery testing with third-party utilities

Apps from Google Play aren't always accurate, but they give a general idea of the battery status.

⚠️ Note: If AccuBattery shows a capacity of 20-30% lower than passport (for example, 3,500 mAh instead of 5000 mAh), but the phone lasts 4-5 hours – most likely, the battery has already been replaced by a cheaper counterpart with less capacity.

A critical sign of cheating: if the AIDA64 battery model is listed as "unknown" or "generic" and the seller claims that the battery is original.

5. Screen check for broken pixels and backlight

Screen defects on Xiaomi are often disguised as "matrix features."

1. Install the Screen Test (or Display Tester) app.
2. Check it out: 🟢 Broken pixels – run the test on monochromatic colors (black, red, green, blue). 🔦 Backlight - at 100% brightness should not be spots or gradient-effect (characteristic of cheap ones) AMOLED into POCO M-series). 🎯 Sensor – Test multi-touch (simultaneous touch 5)+ finger-point).

Typical Xiaomi screen problems:

• 🔴 "Yellow spots on AMOLED after 1-2 years of use (degradation of the organic layer).
• 🔵 "Gradient" backlights IPS-matrices in Redmi 9/10 (factory-assembly defect).
• ⚪ "Sensor dead zones at the edges (often after screen replacement in unofficial services).

6. Diagnostics of iron: processor, memory, cameras

For a comprehensive test, use:

• 🖥️ 3DMark Geekbench – check the performance CPU/GPU. Compare the results with the references for your model at geekbench.com.

⚠️ Note: If Geekbench results are below the benchmark by 30%+, It could mean:

⚠️ Trottling due to overheating (Snapdragon chipset) 732G into POCO X3 warm up to 85°C when loaded. Motherboard defect (occurs after artisanal repairs); Custom core use (if the phone is rooted).

7.Authentication and history of the device

If you are buying a phone from hand, check:

1. IMEI: Type *#06# -- compare the number to what's on the box and under the battery. Check on imei.info -- if the model doesn't match, the phone has been reflashed.
2. Serial number: Dial ##7666## (on some models) or check in Settings → About phone. Check with the number on the box and under the battery (if removable).

History of repairs

• Ask the seller for checks from the service center (on Xiaomi they are tied to IMEI).
• Use Mi Verify (only for officially imported devices).

Critical sign of fraud: If the seller refuses to show IMEI or update history (Settings → About Phone → System Update → Update History), most likely, the phone is wanted or with a “gray” firmware.

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Even if all tests are successful, be sure to check the phone for a Mi Account attached (go to Settings → Accounts).If the previous owner did not untie the device, you will not be able to reset it to factory settings!

FAQ: Frequent questions about Xiaomi's diagnostics