Checking Xiaomi phone before buying: a step-by-step guide with photos and tips

Buying a Xiaomi smartphone is a big decision, especially if it’s a used device or buying in unofficial stores. Even new devices out of the box can have hidden defects, fake components or software “surprises.” According to 2026 statistics, up to 15% of Xiaomi smartphones in the secondary market are sold with malfunctions or after unskilled repairs.

We'll look at all the critical aspects, from visual inspection of the case to deep diagnostics of iron and software. AMOLED-screens (e.g. Xiaomi) 13/14 series K60), where there are often problems with the "burnout" of pixels, as well as budget devices (Redmi Note) 12, POCO X5), And at the end of the day, you'll find an interactive checklist for quick checks and answers to a lot of questions.

1. Originality Check: How to Distinguish a Xiaomi Fake

A fake Xiaomi may look almost like the original, but inside you, you'll have cheap component counterparts, stripped-down specs, and no support for official updates. The first thing you need to do is check the serial number and external signs of authenticity.

Start by inspecting the package (if you are buying a new phone):

• 📦 The box must be made of dense cardboard with a clear seal of the Mi logo or Redmi/POCO. There is a sticker at the bottom of the IMEI, serial number and barcode.
• 🔍 Hologram on boxes of flagship models (Xiaomi 14 Ultra, MIX Fold 3 changes color when tilted. on budget series (Redmi) A2) It might not be.
• 📱 The film on the screen of the original devices has the Xiaomi logo or the inscription “Screen Protector” with microtext.

The most reliable way is to check IMEI through official services:

1. Dial on the phone keyboard *#06# - will appear IMEI (15 numbers).
2. Go to IMEI.info or the official Xiaomi service (verify.mi.com).
3. Enter. IMEI Compare the data with the model’s stated characteristics.

⚠️ Note: If the seller refuses to show the box or check IMEI "And then, it's a question of originality. IMEI, numeral.

2. External inspection: what gives a broken or restored phone

Even if the phone turns on and works, physical damage can be serious internal problems.

• 🔦 Microcracks on the glass -- light the screen at an angle. AMOLED-Xiaomi 13 Pro, Redmi K70) cracks are almost invisible when the screen is turned off, but appear when turned on.
• 📏 The gaps between the body and the screen are a sign of a replacement display or a fall.
• 🎨 Uneven coloring – the original Xiaomi body color is homogeneous. If you notice the transitions of shades (especially on glossy models Xiaomi Civi 3), the phone was painted after repair.
• 🔊 Speakers and microphones -- hold your phone to your ear and shake it.

Check the ports and buttons:

• ⚡ USB-Type C: Insert the cable effortlessly. If the connector is a luftite, it will soon have to be changed (repair costs from 1,500). ₽).
• 🔋 Slot for SIM-If you want to put a card in and take out the tray, it should move smoothly, without creaking.
• 🔑 Power and volume buttons – press them 10-15 times. If you hear a crunch or they fail, the mechanism is worn out.

💡

Use your phone's flashlight to inspect the ports -- there should be no oxidation (green plaque) or dirt inside. These are signs of moisture getting in.

Screen Diagnostics: How to Identify Broken Pixels and Sensor Problems

The screen is the most expensive component of a smartphone, and its defects are often hidden.

1. Broken pixel test: Install Screen Test (available on Google Play). Turn on black, white, red, green and blue in turn. Look for glowing dots (broken pixels) on black backgrounds, stripes or uneven backlights on color.
2. Sensor Check: Open Settings → Display. → Touch test (some models may have different paths) swipe across the screen area — the line should be flat, without tears. Press in corners and edges — where the sensor most often fails after falls.

Burnout test (for the purpose of AMOLED)

• Turn on the white background to full brightness.
• Look at the angle – if you notice the contours of icons or keyboards, the screen is worn out.

Pay special attention to models with high refresh rates (POCO F5, Redmi Note 13 Pro+). If the screen “twitches” when scrolling or flickers, it may be a defect of the matrix or display driver.

⚠️ Attention: On Xiaomi with LTPO-screens (Xiaomi 13 Ultra, MIX Fold 2) check the fluidity of the adaptive frequency. Go to Settings → Display. → Update frequency and select "Adaptive." When scrolling through the menu, the frequency should fluctuate smoothly from 1 Hz to 120 Hz.

4.Iron testing: processor, memory, battery

Hidden iron problems don't show up immediately, but they can make your phone unusable after a few months.

1. Checking the processor and RAM

• 📊 Install. CPU Throttling Test (from Google Play) Run the test for 15 to 20 minutes. If performance drops by more than 30%, the processor overheats or degrades.
• 🔥 Open AnTuTu Benchmark and run the full test. Compare the result to the reference values for your model (for example, the Snapdragon 8 Gen 2 in Xiaomi 13 should dial 1,200,000).+ score).

Battery diagnostics

• 🔋 Type #4636## into your phone number, select "Battery Information." Check the level and health setting. A value below 80% indicates severe wear and tear.
• ⚡ Install AccuBattery and charge the phone to 100%, the app will show the real capacity. For example, if the Redmi Note 12 Pro with the declared 5000 mAh left 3800 mAh, the battery is worn out by 24 mAh%.

3. drive test (eMMC/UFS)

• 💾 Install. A1 SD Bench and check the read/write speed. UFS 3.1 (e.g. in the POCO F4 GT) Normally: Reading 1500+ MB/s, record 800.+ If the values are lower by 30-40%, memory degrades.
• 🔍 Run it in. ADB Command: adb shell dumpsys diskstats Look for lines with bad_blocks. If the value > 0, memory damaged.

⚠️ Note: Xiaomi with virtual RAM (Redmi Note 13 Pro, POCO X5 Pro) check the settings in Settings → Additionally. → RAM Extension: If the option is disabled and the seller claims the phone is "like new," it could have been reset after heavy use.

5. Software verification: firmware, root, viruses

Unofficial firmware, root access and viruses can make a phone unstable or dangerous to use.

1. Verification of originality of firmware

• 📱 Go to Settings. → The phone. → Version. MIUI. Compare the official version on the website MIUI Downloads.
• 🔍 If the firmware name has suffixes xm, eu or ru (for example, V14.0.4.0.TMCRUXM), The presence of dev, beta or non-standard designations indicates custom firmware.

2. Search for root rights

• 🛡️ Install Root Checker from Google Play. If the app shows "Root access: Yes," the phone is hacked.
• 🔧 Check if applications like Magisk Manager, SuperSU or busybox are on the installed list.

3. Virus scanning

• 🦠 Use Malwarebytes or Dr.Web Light for deep scanning. Notice apps with Chinese characters in the title — they're often installed by scammers.
• 📂 Check the folder. /system/app through a file manager (e.g. Solid Explorer) APK-Files - Sign of Infection.

Test for "gray" functions

• 📡 Turn on Developer Mode (7 times click on Version) MIUI in settings) and check: Settings → Additionally. → For developers → Debugging by USB If the option is turned on without your knowledge, the phone could be used for testing or mining.
• 🔄 Reboot your phone and look at the boot time. If it's more than 40 seconds, there may be hidden processes in the system.

Diagnostics of camera, speakers and sensors

Cameras and sensors often break down after falls or moisture, but the sellers don't tell you about it.

1. Camera test

• 📸 Take a photo on the main, front and wide-angle camera under different conditions: 🌞 Bright lights – check for no spots and overlights. 🌃 Dark - turn on night mode. The photo should not be noise (colored dots). 📄 Text -- take a picture of the fine print. If the letters are blurry, there's a problem with focus.
• 🎥 Record the video in 4K@60fps (If supported, there should be no "ragged" frames or artifacts when playing.

Verification of speakers and microphones

• 🔊 Turn the music on at maximum volume. The sound should be clear, without wheezing. 13T, POCO F5) Check the balance – the sound should be the same on both sides.
• 🎤 Record your voice memo and listen. If you hear interference or a voice sounds like a barrel, the microphone is damaged.

3. Sensor test

• 📱 Install the Sensor Test (like Phone Tester) and check: Gyroscope/accelerometer — tilt the phone, the ball on the screen should move smoothly. Approximation sensor — during the call, the screen should go out when you lift it to the ear. Compass — the arrow should respond to the turns of the phone. Light sensor – cover the top of the phone with your hand – the brightness of the screen should change.

⚠️ Note: Xiaomi with infrared port (Redmi Note 12, POCO M5) Check it with Mi Remote, and if the remote doesn't recognize the signals, the port is faulty (repair costs 1,000 to 2,500). ₽).

Communications check: LTE, Wi-Fi, Bluetooth and GPS

Communication problems don't come up immediately, but they can make your phone useless.

1. Mobile network test

• 📶 Put it in. SIM-Map and check: Internet speed via Speedtest. 4G normality - 50+ Mbps, for 5G — 200+ Mbit/s. Communication stability — call another phone and walk around the room. If the call stops, antenna problem. Range support — type ##4636##, select Phone Information. Set preferred network type should be available LTE and NR (5G) (if maintained).

2. Diagnostics of Wi-Fi and Bluetooth

• 📶 Connect to Wi-Fi at 2.4 GHz and 5 GHz. Speed should be close to maximum for your router.
• 🔗 Check Bluetooth: Connect your headphones and assess the sound quality (no stuttering) Pass a file size of 50-100 MB. Speed should be at least 2-3 MB / s (for Bluetooth 5.0)+).

3. Test. GPS

• 📍 Install. GPS Test and wait for the coordinates. In urban environments, the accuracy should be 5-10 meters. If the signal is lost or the coordinates "jump", the module GPS faulty.
• 🚗 Turn on navigation in Google Maps or Yandex.Maps and walk 200-300 meters. the route should be displayed smoothly, without jumps.

💡

If the phone's not catching. 5G, Although the model supports it, check the settings. APN. Sometimes it is enough to reset them to the factory (Settings) → SIM-maps and mobile networks → Access points (APN) → Reset).

8 Final Check: What to Do Before Payment

If all tests are passed, there are a few critical steps before buying:

1. Activation Check: Make sure the phone is not tied to the previous owner's Mi Account. Go to Settings → Accounts. → If it's someone else's email, ask the seller to come out and reset the phone. FRP (Factory Reset Protection, after reset, you will need to enter the username / password of the previous owner. Without this information, the phone will become a brick".
2. Test for overheating: Start the game (Genshin Impact, Call of Duty Mobile) for 15-20 minutes. the CPU temperature should not exceed 45-50°C (check through) AIDA64). If the phone is heated to 60°C+, This is a sign of thermal paste wear or battery problems.

Documentation verification

• The new phone must have a check with the date of purchase (for guarantee).
• Ask for a warranty card (if it is still valid) or a check for repair (if it was).

If you buy a phone from hand, make a receipt indicating:

• Models and IMEI.
• Conditions ("working, no claims").
• Amounts and dates of transfer of money.

⚠️ Attention: On Xiaomi with NFC Check it with Google Pay or Mi Pay, and if the payments don't go through, the chip is damaged (it costs 1,500 to 3,000 to replace). ₽). Especially relevant for the Redmi Note 12 NFC and POCO X5 Pro.

💡

Never accept a prepaid or crowded meeting without the possibility of testing, and the best option is to check in at a service center (many Mi Stores offer such a service for 300-500 dollars). ₽).

FAQ: Answers to Frequent Questions