Owners of modern Chinese smartphones often face the need to identify their device, which may be required when registering on the forum, issuing a warranty, unlocking the bootloader, or simply to verify the authenticity of the gadget. Serial number (SN) is a unique identifier that is assigned to a particular instance in the factory, unlike IMEI, which is responsible for communication.
Many users get lost when standard methods of searching information don’t work or the MIUI shell interface (HyperOS) seems confusing. In this article, we will explore in detail all possible ways to obtain this data, including hidden engineering menus and system commands available without root rights.
Knowing where to find Serial Number will help you avoid fraud when buying used equipment and speed up the process of contacting technical support. Let's look at how to extract this information in a variety of ways, from simple to more complex.
Search for information in the system menu "About the phone"
The most obvious and safe way to find out device identifiers is to look at the standard settings menu. However, depending on the firmware version and region, the location of the data may vary slightly. Usually the path is as follows: Settings → About the phone → General information or All settings.
In the list that opens, you'll see a lot of lines, including the Android version, the MIUI version, and other technical information, and you'll need to find the Serial Number line, which is an alphanumeric combination of code and is unique to your device.
Sometimes the system hides some of the data for security reasons or because of the specific certification in a particular region. If you don't see SN right away, try clicking on the "MIUI Version" or "Kerole Version" several times, although most often this opens the developer menu rather than showing hidden codes.
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If the serial number does not appear in the General Information menu, try switching the system language to English – sometimes this forcibly displays hidden fields.
It is worth noting that two-symbol devices will also display two numbers. IMEI, slot-like SIM-Don't confuse them with the serial number of the device itself, because it's the warranty service that requires it. SN.
Use of engineering USSD-code-check
For more in-depth diagnostics and technical information in the Xiaomi, Redmi and POCO smartphones, there is a special engineering menu, accessed through a standard phone dialer using a secret code.
You need to open the Phone app and dial the combination ##6484##. Once you enter the last digit (* or #), the menu should open automatically, without having to press the call button. If the code did not work, it is possible that your version of the shell will block this access.
- 📱 On the menu that opens CIT (Customer Information Test: Select Version or Hardware info.
- 🔍 In the list of parameters, find the Serial Number or SN.
- 📝 Copy the value or write it down, as you can’t go to the main screen without closing the test.
What if the code doesn't work?
The advantage of this method is that it works even if the phone is not fully activated or has no Internet access, and the main thing is that the device can start the dialing interface.
Checking through the ADB command line (for advanced)
If you have access to a computer and have ADB (Android Debug Bridge) drivers installed, you can get device information directly from the system without going through the GUI, which requires you to include USB debugging in the Developer Menu.
Connect your smartphone to your PC with a cable, open the command line on your computer, and enter a command to check the connection: adb devices. If the device is determined, you can request a serial number.
adb shell service call iphonesubinfo 1The result of the execution of the command will return a string with data, which will contain the desired identifier. Note that the output can be presented in Unicode or HEX format, and you will need to decode the string to see the readable serial number.
☑️ Preparation for work with ADB
This method is especially useful if the phone screen is broken and you can not click on menu items, but the touchscreen is partially functional or you can control the device with a mouse via OTG.
Alternative methods: box and stickers
When the phone is turned off or doesn't show signs of life, the only source of information is the physical packaging, and there's always a sticker with basic data on the back or side wall of the original box.
Here you'll find barcodes, IMEIs, and Serial Numbers. The data on the box should be exactly the same as the ones on the system. Even a single digit difference could indicate that the box is glued or the device is assembled from different parts.
| Parameter | Where to look on the box | Data format |
|---|---|---|
| IMEI 1 | Top of the sticker | 15 numbers |
| IMEI 2 | Under IMEI 1 (for 2 SIM) | 15 numbers |
| Serial Number (SN) | Separate line with code | Letters and numbers (10-12 Symv.) |
| MAC Address | Near IMEI | Pairs of symbols through the colon |
Also, a sticker with duplicate information is often under the tray. SIM-On the back of the device, if it's removable, it's useless to look for a sticker on the case on modern moisture-protected monoblocks, because there's only a logo and a marking. CE.
Why You Need to Know the Serial Number of Your Device
Understanding the importance of SN goes beyond mere curiosity, and it's the key to managing the life cycle of your gadget in the manufacturer's ecosystem, and without it, you can't have full service.
First, it's a warranty: When you go to an authorized service center (ASC), the first thing you're going to do is ask for a check and a box or a menu to check against the base, and if the serial number doesn't read or match, you may be denied warranty repairs.
Second, authentication: Xiaomi has a verification service on its official website where you can enter SN and IMEI, and it will tell you if the device is original, when it was activated, and if the extended warranty is still valid.
⚠️ Note: Never post photos of a box with a visible serial number and IMEI Intruders can use this data to clone a device or to commit fraud with a guarantee.
In addition, when unlocking the bootloader through the official Mi Unlock tool, the program automatically reads this data and links the Mi Account account to this unique hardware identifier.
What to do if the serial number is not displayed or is equal to Unknown
A situation where a dashboard, the word Unknown, or a set of zeros is displayed in the serial number field is an alarm bell, which may indicate a software failure, a failed firmware reflash, or a hardware problem.
Often this problem occurs after trying to install global firmware on the Chinese version of the phone (or vice versa) without proper preparation (memory partitions), in which case the persist file, which stores calibration data and unique identifiers, could be damaged or erased.
- 🔄 Try to complete the reset (Settings) → The phone. → Resetting settings, pre-saving data.
- 💻 Run the flashing device through your computer using the official Mi Flash Tool and Fastboot mode.
- 🛠 If software methods don’t help, the memory chip is probably damaged. eMMC/UFS, Replacement in the service center.
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The absence of a serial number in the system ("Unknown") almost always means damage to the persist partition or a motherboard issue, making the phone a "brick" for some features.
In rare cases, on some custom firmware (Custom ROM), the field may remain empty if the builder has not added the correct script to read it, in which case a return to the runoff (official firmware) solves the problem.