How to restore the serial number on Android

The absence of serial number or IMEI in the settings of an Android smartphone, which often occurs after unsuccessful firmware, data reset or damage to the system partition, immediately blocks the operation of the mobile network and makes it impossible to make calls.

Restoring lost data requires care and strict adherence to instructions, since incorrect actions can lead to complete inoperability of the communication module. In this article we will examine in detail software methods for returning identifiers, the use of engineering menus and specialized software. You will have to learn how to check the current status of the device, what commands to enter into the terminal and when flashing it is no longer possible.

Diagnostics of the problem and checking current data

Before taking any active recovery actions, you need to make sure that the identifiers have been lost. Users often confuse the lack of display of a number in the settings with its real absence in the system. For initial verification, enter the universal code *#06#on the phone keypad. If numbers appear on the screen, it means that the NVRAM database is intact, and the problem lies only in the display of the interface.

If instead of numbers you see the words “Null”, “000000000000000” or a connection error message, the situation requires intervention. It is also worth checking the information in the menu Settings → About phone → General information. The absence of IMEI in this partition confirms that the partition NVRAM is damaged or erased. This is a critical error that cannot be ignored, since without it the phone turns into something like a Wi-Fi tablet.

⚠️ Attention: If the IMEI is displayed as invalid, do not try to immediately reflash the device using standard methods. Regular firmware may not affect the damaged calibration section, and the problem will remain unresolved.

Additionally, it is worth using applications like Device Info HW or Phone Info SAM (for Samsung), which read data directly from the modem. They show a more detailed picture of the status of the radio module. If the application reports that the IMEI is unknown, it means that the connection between the operating system and the radio part is completely lost. In this case, software recovery through simple settings menus is no longer possible.

Using the engineering menu for recovery

On many devices running processors MediaTek and some older models Qualcomm there is a hidden engineering menu. It allows you to manually enter IMEI into the appropriate database fields. This menu is usually accessed via code ##3646633## or ##4636##. The interface may differ depending on the version of Android and the manufacturer's shell, but the logic of the actions remains similar.

After entering the menu, you need to go to the tab Connectivity, then select CDS Information and item Radio Information. Here you will see a field IMEI 1. You need to enter a command like AT+EGMR=1,7,"YOUR_IMEI". Please note that there must be spaces between the command and the quotes. For the second SIM card slot, use the command AT+EGMR=1,10,"YOUR_IMEI_2".

What to do if the fields are inactive?

If you cannot enter text in the fields of the engineering menu, which means you do not have root access. Try installing the Mobile Uncle Tools application, which can provide access to these settings through its interface, or obtain superuser rights.

After entering the command, press the button Send at command. The system should respond with a message OK. This means that the data has been successfully written to non-volatile memory. However, on some new versions of Android, access to these functions is blocked at the system kernel level. In this case, the method will not work, and you will need to use a PC.

• 📱 Make sure that the SIM card is inserted before entering the menu.
• 🔢 Enter the IMEI without spaces or dashes, only numbers.
• 💾 After entering the command, be sure to reboot the device.

Recovery via root access and terminal

If the engineering menu is not available or does not save changes, the only software solution is to obtain superuser rights (Root). This gives full access to system files, including damaged partitions. To do this, use utilities like Magisk or KingRoot. After obtaining root access, you need to install a terminal emulator, for example Terminal Emulator.

In the terminal, commands are entered to overwrite the modem configuration files. First you need to gain privileges by entering the command su and confirming access in the pop-up window. Then the partition is mounted in recording mode. The command looks like mount -o rw,remount /dev/block/mmcblk0pX /system, where X is the partition number, which varies from device to device.

su
echo -n 'IMEI_1' > /persist/imei
echo -n 'IMEI_2' > /persist/imei2
reboot

This method is extremely risky, since the wrong path to the file can lead to bricking the phone. Path /persist/ is relevant for many modern smartphones, but on older models the data can be stored in /efs/ or /nvram/. Before performing operations, it is strongly recommended to create a full backup of the partition EFS or Persist via Recovery mode.

⚠️ Attention: Incorrect use of commands in a terminal with root access can permanently delete antenna calibration data. As a result, the phone will see the network, but the signal quality will be zero.

Using specialized software on a PC

When methods directly on the device are exhausted, computer utilities come to the rescue. For processors MediaTek the gold standard is the app SN Writer or Maui Meta. To work with them, you will need drivers VCOM and a switched off phone, which needs to be put into download mode (usually by holding down the volume buttons when connecting the cable).

In the app SN Writer you need to select the device type (Smartphone), specify the path to the file target_config (often goes to complete) and press the button Start. Next, the app will ask you to enter the IMEI and serial number. After entering the data and pressing Write recording occurs in the phone's memory. The process takes a few seconds, after which a success message appears.

Processor	Recommended utility	Connection mode	Difficulty
MediaTek (MTK)	SN Writer Tool	Boot ROM / Preloader	Medium
Qualcomm	QPST / QCAL	EDL Mode (9008)	High
Spreadtrum	ResearchDownload	Upgrade Mode	Low
HiSilicon	DC-Phoenix (paid)	Test Point / Fastboot	Very high

For devices based on Qualcomm the situation is more complicated. The use of paid boxes or specialized service accounts is often required, since their section EFS is encrypted. Free methods rarely work and depend on the specific modem model. In such cases, it is easier to contact specialists who have licensed equipment.

Return to factory firmware (Stock ROM)

Sometimes file system damage is logical in nature, and restore IMEI can be done with a simple clean installation of the original software. Third-party firmware (Custom ROM) often does not contain the correct scripts to initialize the partition with identifiers. Returning to Stock ROM via mode Fastboot or Recovery can automatically restore communication with the modem.

To do this, you need to find the official firmware image specifically for your model and region. Universal firmware may not be suitable. After downloading the file to the computer, the phone is switched to bootloader mode, and the command is executed fastboot flash persist persist.img (if the partition file is in the archive) or a complete flashing through a script flash_all.bat.

This method is safer than manually editing files, but it will completely delete all user data from the device. If the reason for the IMEI loss was a software conflict, then after installing the stock version the problem will disappear. Otherwise, if the partition is physically worn out or damaged, flashing it will not help.

⚠️ Attention: When flashing via Fastboot, make sure that the Bootloader version on the phone matches the firmware version. Mismatch versions can cause the phone to stop booting at all.

Prevention and important warnings

The problem of losing the serial number often arises due to the carelessness of users when obtaining root access or installing custom recovery. To avoid this in the future, always make a backup copy of the partition EFS or Persist immediately after obtaining superuser rights. Use applications like EFS Professional or functions in TWRP Recovery for this.

You should also avoid installing unverified patches and mods that promise to “improve the signal” or “unblock the network.” They often modify modem files, which leads to loss of IMEI. If you plan to sell the phone, make sure that all identifiers are in place, since a device with a zero IMEI cannot be legally activated in the networks of most operators.

Remember that changing the IMEI to a number from another phone is illegal in many countries. All methods described are intended solely for restoring your own the original number indicated on the device case or in the warranty card. Using other people's identifiers may result in the device being blocked by the telecom operator.

Is it possible to restore IMEI without a computer?

On older Android devices (versions 4-6) this was possible through the engineering menu. On modern Android 10-14, access to the IMEI entry is closed at the kernel security level, so it is almost impossible to do without a PC and special cables.

Frequently asked questions (FAQ)

What should I do if, after restoration, the IMEI disappears again?

This indicates deep damage to the NVRAM partition or a problem with the memory chip itself. Try doing a full data format (Wipe Data/Factory Reset) after writing the IMEI. If this does not help, you may need to replace the board or resolder the memory chip at a service center.

Does an unlocked Bootloader affect the loss of IMEI?

The unlocked bootloader itself does not remove IMEI. However, the unlocking process is often accompanied by a data reset, and if the firmware crashes at this point, the partition with identifiers may suffer. On some devices (for example, Huawei) unlocking is not possible at all without the risk of losing functions.

Is it possible to restore the serial number on a phone without Root?

Without root access, access to the system files where the IMEI is stored is closed. The only option without root is to flash the device with an official recovery via a computer, which itself will write the correct data if it is contained in the firmware image.

Is it safe to use apps like "Chamelephon"?

The Chamelephon application is designed to generate random IMEI on MediaTek devices. It is unsafe and illegal to use unless you restore your original number. In addition, it does not work on new versions of Android due to changes in the security architecture.

Where can I get my original IMEI if the box is lost?

If the phone still somehow turns on, look at the sticker under the battery (if it is removable) or on the back cover. Also, the number is often duplicated in the purchase receipt or in the personal account of the telecom operator if the phone was previously registered on the network.