How to restore the serial number and IMEI on Android after flashing

After installing custom firmware or an unsuccessful software update, users often encounter a critical error: the phone loses the ability to register with the operator’s network. A no-signal icon appears in the status bar, and an incorrect or null identifier is displayed in the device settings. This is a direct consequence of damage or deletion of the partition EFSwhere the unique data of your device is stored.

Recovery IMEI is a process that is not just desirable, but mandatory for the legal use of the gadget. Without the correct serial number, you will not be able to make calls, use the mobile data or even send SMS. Moreover, a device with a “broken” identifier may be blocked by telecom operators, since it looks like a fake device in the eyes of the network infrastructure.

The procedure for restoring the functionality of the radio module varies depending on the processor of your smartphone. For chips MediaTek there are specialized utilities that allow you to write data manually, while devices based on Qualcomm require more complex manipulations with the engineering menu or patches. In this article we will look at the most effective methods for returning communication to your Android device.

Diagnosing the problem and checking the current status

Before taking active steps, you need to make sure that there is a problem and exclude software failures that can be fixed by simply restarting the services. Enter the universal command in the “Phone” application *#06#. If two correct 15-digit numbers are displayed on the screen, the problem may lie in the network settings or SIM card, and not in the firmware.

However, if you see the message “Null”, “000000000000000” or the field is completely empty, this confirms the loss of data from the partition NVRAM. It is also worth going to the menu Settings → About phone → Status (the path may differ depending on the version Android) and check the number displayed there with what is indicated on the factory sticker under the battery or on the box.

⚠️ Attention: If after the firmware your IMEI has disappeared, but Wi-Fi and Bluetooth are working properly, then only the cellular radio module is affected. If Wi-Fi also does not work, the damage to the system partition is deeper.

Sometimes the system sees the SIM card, but cannot determine the network type. This is a classic symptom of baseband (Baseband) being out of sync with the operating system. In such cases, standard factory reset methods are useless, since they do not restore deleted calibration files.

Preparing tools and drivers

To successfully restore the serial number, you will need a computer running Windows, a working USB cable and a full charge of the smartphone battery (preferably more than 50%). A key element of success is the correct installation of drivers, without which the PC simply will not see the phone in the required mode.

Owners of chip-based devices MediaTek need to install MTK VCOM Drivers. These drivers allow the computer to communicate with the phone in deep firmware mode. The installation should be carried out with the device turned off, holding the volume buttons while connecting the cable. For processors Qualcomm you need drivers QPST or specific drivers Diag.

You will also need specialized utilities. The most popular and universal app for MediaTek is MTK Droid Tools. It can make backups of an EFS partition and restore them. For more complex cases when automatic recovery does not work, use the utility SN Writer or Maui Meta.

• 📱 Download and install the latest versions of ADB and Fastboot drivers for your brand.
• 💾 Find the original firmware for your model to extract the calibration files from there (NVRAM.img or modem.bin).
• 🔋 Make sure that the USB cable supports data transfer, and not just charging.

Do not forget that working with engineering utilities requires superuser rights. Must be received on your device root access. Without them, most apps simply will not be able to access protected memory sections and write new data there.

Recovery method via MTK Droid Tools

This method is considered the safest and easiest for devices on database MediaTek. The app MTK Droid Tools automatically reads the current state of the phone and offers to restore damaged (partitions). Run the utility on your PC and connect your smartphone with USB debugging enabled.

After the app detects the device (the indicator turns green), go to the roottab. Here you are interested in the button IMEI: NVRAM. By clicking on it, you will open a window where you can enter your original numbers. Enter the IMEI for the first slot (IMEI 1) and, if necessary, for the second (IMEI 2).

Enter the numbers carefully, without spaces or dashes. An error in one digit will make the number invalid.

After entering the data, press the button Replace or Write. The app will send a command to the phone, and the data will be written to non-volatile memory. Once the process is complete, you must reboot your device. If everything went well, when you enter the command *#06# you will see your numbers.

⚠️ Attention: Some modern versions of Android (10, 11, 12+) have enhanced protection for the Protect section. Data recording may be blocked by a security system. In this case, you need to temporarily disable the protection through the engineering menu.

What to do if MTK Droid Tools does not see the phone?

Make sure that USB debugging is enabled. Try a different USB 2.0 port (not 3.0). Reinstall the VCOM drivers in Device Manager, selecting the port with the yellow exclamation mark.

Using the SN Writer utility to write data

If the previous method did not work, the utility SN Writercomes to the rescue. It works directly with configuration files and often solves problems where other tools cannot. To get started, download the version of the app that matches your connection type (USB or UART).

Run SN_Writer.exe as administrator. In the settings window (button Target Type) select Smart Phone. Next, click Com Port and specify the port number that appeared in the Windows Device Manager after connecting the phone in Meta Modemode. To enter this mode, you usually need to turn off the phone and connect the cable while holding both volume buttons.

In the main app window, check the boxes next to the parameters that you want to restore. Usually it is IMEI, Barcode (bar code) and sometimes WiFi Address. Click the button Write Start and connect your phone. The recording process will take a few seconds, after which a success message will appear.

Parameter	Description	Required
IMEI	Unique device identifier	Yes
Barcode	Case serial number (S/N)	No
WiFi MAC	Network adapter address	Desirable
Bluetooth	Bluetooth module address	No

It is important to understand that the utility SN Writer requires a file auth_file or the correct certificate for some new models. Without this file, recording may be blocked at the hardware level. In such cases, finding a suitable auth file becomes a separate task.

Manual editing through the Engineering menu (Engineering Mode)

For experienced users, it is possible to register IMEI directly through the engineering menu of the smartphone itself. This method does not require a computer, but does require extreme care. You can enter the menu by dialing a number ##3646633## or using the application Mobileuncle MTK Tools.

In the interface that opens, go to the tab Connectivity, then select CDS Information. Next, open item Radio Information. Here you will see a text box with AT commands. To record the first IMEI, enter the command:

AT+EGMR=1,7,"YOUR_IMEI_1"

Pay attention to the syntax: quotes are required, and there should be no extra spaces between parameters. For the second SIM card slot, the command will differ only in the last parameter:

AT+EGMR=1.10,"YOUR_IMEI_2"

After entering the command, press the button Send AT Command. The system should respond OK. If you receive an error, write protection may be active. In this case, first try entering the command AT+EGMR=0,7,"" to read the current value to check the connection with the modem.

This method works on most old and middle-aged MediaTek devices. However, on new models with Android 9 and higher, access to these commands is often closed by the manufacturer, and attempts to enter them are ignored by the system.

Features of recovery on Qualcomm processors

IMEI recovery on devices with chips Qualcomm (Snapdragon) is radically different from MediaTek. There are no simple utilities like MTK Droid Tools. The main method of operation involves using a set of tools QPST (Qualcomm Product Support Tools) and mode Diag.

First you need to activate the diagnostic port. This is done through the hidden dialing menu (for example, ##717717## on some models) or through the ADB command:

adb shell setprop sys.usb.config diag,adb

After activation, the port Qualcomm HS-USB Diagnosticswill appear in the device manager. Run the utility QPST Configuration, add a new port and open QCN File Manager. Your task is to find a backup copy of the file .qcnmade before the problems arose and restore it. If there is no backup, the process is complicated by the need to find a donor file for your model.

⚠️ Attention: Recording an incorrect QCN file from another phone model can lead to a complete “bricking” of the modem. Restoring it will be extremely difficult; paid software for service centers is often required.

There are also paid boxes and dongles (for example, Octoplus, Chimera) that automate this process for qualified craftsmen. For an ordinary user, an attempt to manually edit QCN without experience can be fatal for the device.

Prevention and creation of backup copies

The best way to combat the loss of IMEI is to create a backup copy of the partition in advance EFS or Persist. This should be done immediately after obtaining root access and before any experiments with firmware. Utilities like TWRP Recovery allow you to create a backup of this partition in the form of an image file.

Save the resulting file not only in the phone’s memory, but also in cloud storage or on your computer. In the event of a failure, you can simply “pour” this image back through recovery, and all network settings will return to their places instantly. It takes a couple of minutes and saves you from hours of searching for solutions.

• 📂 Use TWRP to backup EFS, Persist and Modem partitions.
• ☁️ Duplicate important files on Google Drive or PC.
• 📝 Write down the IMEI from the box in the notes on your phone and print the sticker.

Remember that the EFS partition contains not only IMEI, but also encryption keys, Wi-Fi and Bluetooth settings. Its loss may lead to the fact that even if you restore IMEI, wireless data transfer will not work.

Is it possible to restore IMEI without root access?

In 99% of cases, no. Access to the NVRAM section where identifiers are stored is closed at the system kernel level. Without superuser rights, no app will be able to write new data there. The only exception is that some service centers have access to the manufacturer's servers for official flashing.

Is it dangerous to change the IMEI to another number?

Yes, it is illegal in many countries. You must enter only the number that was assigned to the device by the manufacturer (indicated on the box). Using foreign or random numbers can lead to blocking of the device by telecom operators and legal problems.

Why does the network not appear after IMEI restoration?

You may have written down the number correctly, but damaged other antenna calibration parameters (RF calibration). The problem may also be the incompatibility of the modem version (Baseband) with the Android version. Try flashing a full dump of the stock firmware using the SP Flash Tool.

Is IMEI reset when updating over the air (OTA)?

Usually not, if the update takes place normally. However, if the upgrade process fails or there is a version conflict, the EFS partition may be wiped out. That is why before any update it is recommended to make a full backup.

⚠️ Attention: Information about recovery methods is provided for informational purposes. Changing device identifiers may violate the laws of your country. The author of the article is not responsible for failed devices.