Changing or restoring the international mobile equipment identifier (IMEI) is one of the most delicate and technically complex procedures in the world of mobile modification. Users are often faced with the need to change this code for various reasons: from a banal network loss after an unsuccessful reset to a desire to bypass operator blocking. However, it is important to understand that IMEI is not just a set of numbers, but a unique passport of your device, rigidly tied to the hardware at the modem level.
The flashing process is radically different from the usual installation of custom firmware (ROM). This is where you tamper with the NVRAM (Non-Volatile Random Access Memory) where critical radio module calibration data is stored. An error at this stage can turn your smartphone into a “brick” with a non-working communication module that cannot be restored using standard methods. In this article we will analyze in detail the technical aspects, available tools and legal nuances.
It is worth noting right away that in most countries of the world, changing IMEI in order to disguise a stolen device or bypass blocking is illegal action. This instruction is intended solely for educational purposes and to restore the device’s original number if it was lost as a result of software failures or incorrect operation of the software.
What is IMEI and why is it changed
IMEI (International Mobile Equipment Identity) is a 15-digit code that is assigned to each cellular-enabled mobile device. This number allows telecom operators to identify a specific device on their network. If the phone is stolen, the operator can block it by IMEI, rendering the device useless for calls in that country. This is why a black market for flashed devices exists, but we will focus on the technical aspects.
The main reason why regular users may need to intervene in this area is the loss of IMEI. This often happens after unsuccessful experiments with root access, installing custom recoveries, or a failure when updating the Baseband. As a result, the phone sees the SIM card, but is not registered on the network, and in the settings it is displayed Null or 000000000000000.
Sometimes owners of dual-SIM smartphones are faced with a situation where one of the slots stops working due to an identifier conflict. In rare cases, enthusiasts try to change the region of the device to unlock certain functions, although modern blocking methods rarely rely on this parameter alone. It is important to distinguish between a software failure and a physical failure of the modem.
⚠️ Attention: Changing the IMEI to someone else's number (for example, the number of a stolen phone) is a criminal offense in many jurisdictions. Telecom operators can track duplicate IDs in real time and block both devices.
Technically, the process of recording a new number affects a section of memory that is usually write-protected by the user. Accessing it requires special rights and tools that are often specific to the processor manufacturer. For example, the methods for MediaTek are fundamentally different from those used for Qualcomm or Samsung Exynos.
Checking the current status and backing up
Before taking any action, you need to know exactly the current status of the identifier and save its original value, if it is still available. This is a critical step because without a serial number you will not be able to legally register the device with the operator in case of problems. The check can be performed in several ways that do not require complex utilities.
The simplest method is to use the engineering menu or USSD request. Enter the code *#06# on the dialing keypad. The screen should display one or two values (for dual-SIM devices). If you see dashes or zeros instead of numbers, it means the NVRAM partition is damaged or erased. In this case, you will need to find the original number.
Where can I find the original IMEI if it has disappeared? Look at the smartphone box - there is usually a sticker with a barcode and the necessary data. Also, the number is often printed on the back cover of the device (under the battery, if it is removable) or on the SIM card tray. For greater reliability, you can go to the operator’s personal account, where you registered the device earlier, or check the warranty card.
- 📦 Check the original packaging of the device - the barcode sticker contains the factory code.
- 📄 Look at the warranty card or purchase receipt, where serial numbers are often entered.
- 🔍 Inspect the SIM card tray or the back cover of the smartphone (if the design allows it).
- 💻 Connect the phone to the PC in ADB mode and enter the diagnostic command.
If you have root access, you can use the terminal for deeper diagnostics. The command su will provide a superuser, after which you can try to read data directly from the system. However, if the partition is damaged, this method may not work. Always make a full backup of the EFS or NVRAM partition before any manipulations using a custom recovery like TWRP.
Before starting any work, make a full backup of the EFS/NVRAM partition via TWRP. This is the only way to guarantee that the radio module will be operational in the event of a fatal error.
Necessary tools and environment preparation
The success of the operation depends 90% on the correct preparation of software and drivers. There is no universal “do it well” button, since processor architectures vary. You will need a computer running Windows (less commonly Linux), a working USB cable and installed specific drivers for your chipset.
For devices based on MediaTek (MTK), the de facto standard is the utility SN Writer or Maui Meta Tool. These apps allow you to write data to protected memory areas through the Preloader or Meta Modemode. For processors Qualcomm tools like QPST (Qualcomm Product Support Tools) or EFS Professionalare often used, which work through the mode Diag.
A critical element is installing the correct drivers. Without them, the computer simply will not see the phone in the required diagnostic mode. Often, users have to disable driver digital signature verification in Windows in order to install modified versions of ADB drivers or specific modem drivers. An error at this stage will result in the software displaying a connection error.
| Processor type | Main software | Connection mode | Complexity |
|---|---|---|---|
| MediaTek (MTK) | SN Writer / Maui Meta | Meta Mode / Preloader | Low |
| Qualcomm | QPST / QXDM | Diag Port | Medium |
| Samsung (Exynos) | Octoplus / Z3X (Box) | Download Mode | High |
| HiSilicon | DC-Unlocker / SigmaKey | Com Port | High |
| Universal | Terminal (ADB) | Root Access | Dangerous |
Also make sure that the smartphone battery is charged at least 60-70%. Although the process of writing to non-volatile memory is fast, interrupting the power supply at a critical moment can damage the partition table. Disable the antivirus on your PC, as it can block the work of low-level utilities, considering them suspicious.
☑️ Preparing for IMEI firmware
Instructions for MediaTek processors (MTK)
Smartphones based on MediaTek chips are the easiest to modify due to their open architecture and the availability of free tools. The process usually takes place in two stages: preparing the device and recording data via a PC. Make sure that you have received root accesson your phone, as this is a prerequisite for most methods.
The first step is to activate the engineering menu. To do this, in the "Phone" application, enter the code ##3646633##. If the code does not work, you will need to install a special application from the Play Market, for example Engineer Mode MTK. In the menu, go to the Connectivitytab, then select CDS Information and Radio Information. Here you can temporarily register IMEI with the AT command, but this will be reset after a reboot.
For permanent recording, we use the utility SN Writer. Run the app on your PC as administrator. In the Target Type field, select Smart Phone. Press the button Com Port and select the port that appeared in the device manager after connecting the switched off phone (with the volume button held down). Enter the desired IMEI in the appropriate fields. Press Start and connect the cable to the switched off device.
AT+EGMR=1.7,"YOUR_IMEI_1"
AT+EGMR=1.10,"YOUR_IMEI_2"
The app will begin the recording process. A progress bar will show the status of the operation. After successful completion (green window), turn off your phone, wait 10 seconds and turn it on. Check the result with the code *#06#. If the numbers are displayed correctly, try making a test call. In some cases, you may need to reset your network settings.
⚠️ Attention: When using SN Writer, do not interrupt the process or disconnect the cable until the indicator shows 100%. Interrupting writing to the NVRAM partition can lead to complete inoperability of wireless modules (Wi-Fi and Bluetooth can also fail).
What to do if SN Writer gives an error?
A common cause of the error is the lack of administrator rights for the app or an incorrect VCOM driver. Try running the utility in Windows 7 compatibility mode and as an administrator. Also make sure that the phone is completely turned off before connecting the cable.
Methods for Qualcomm and other platforms
Devices based on Qualcomm require a more complex approach, since access to the diagnostic port (Diag Port) is often closed by the manufacturer. To open it, you usually need to enter a special command via ADB or have root access. Without an open Diag port, apps like QPST will not see the device.
To open the port, run the following commands in the ADB console:
adb shell
su
setprop sys.usb.config diag,adb
After this, a new device "Qualcomm HS-USB Diagnostics" should appear in the Windows Device Manager. If this does not happen, your firmware may block this function at the kernel level, and you will need to replace the modem firmware.
In the QPST Configuration utility, add a new port and run the tool EFS Explorer or specialized scripts for recording IMEI. The process here is less standardized than MTK and often depends on the specific model. For Samsung owners on Exynos, the situation is even more complicated: without paid boxes (Z3X, Octoplus), it is almost impossible to change IMEI programmatically due to hardware protection Knox.
There is also a method through a terminal with root access, which theoretically works on many devices, but carries high risks. It involves direct writing to the modem configuration files. It should only be used by experienced users who understand the structure of the Android file system. An error in one byte can make recovery impossible without soldering.
- 🔓 Open the diagnostic port via the ADB command or the engineering menu.
- 💻 Install the Qualcomm HS-USB Diagnostics 9091 drivers.
- ⚙️ Use QPST or a specialized IMEI calculator to generate the file.
- 💾 Write the file to the /persist or /EFS partition via a file manager with root access.
For Qualcomm processors, the key step is to open the diagnostic port (Diag Port). Without this step, no app will be able to interact with the modem at the IMEI record level.
Possible problems and ways to solve them
Even if you strictly follow the instructions, unforeseen difficulties may arise. The most common problem is Invalid IMEI or "Invalid number". This means that the checksum does not match the numbers themselves. IMEI is not a random set of numbers; the last digit is calculated using the Luhn algorithm based on the previous 14. If you entered the number manually with an error, the phone will reject it.
Another common situation is that the IMEI is registered, but after a reboot it returns to null. This is a sign that the NVRAM partition is write-protected by the current system kernel or recovery. In this case, the only thing that helps is flashing the stock image of the modem (Modem/Radio) via Odin (for Samsung) or SP Flash Tool (for MTK) before attempting to record.
Sometimes after changing the IMEI, the Wi-Fi or Bluetooth signal disappears. This happens because the MAC addresses of wireless adapters are stored in the same NVRAM section. If the utility records it incorrectly, this data may be overwritten. The solution is to restore the EFS partition backup made before the start of the experiments, or find an NVRAM dump specifically for your device model on specialized forums.
⚠️ Attention: If after all the manipulations the phone does not see the network, but the IMEI is displayed correctly, the problem may not be in the number, but in the frequency ranges (Band). Make sure that the modem version supports the frequencies of your telecom operator.
In the event of a complete loss of communication and the impossibility of recovery using software methods, only hardware repair remains. Service center specialists can resolder the memory chip or use programmers to directly write data to the chip, bypassing processor protection. However, the cost of such a service is often comparable to the price of a used device.
Why does the IMEI disappear after flashing the system?
When installing custom firmware, the persist or efs section is sometimes formatted. To avoid this, you need to remove the formatting commands for these partitions in the installation scripts (updater-script), or backup them in advance and restore them after installation.
Legal aspects and security
It is important to clearly understand the line between restoring the functionality of your device and fraud. In Russia, the European Union and the United States, there are strict laws regulating the circulation of telecommunications equipment. Intentionally changing the IMEI on a device that is wanted or blocked for non-payment is interpreted as a forgery of an identification number.
Telecom operators are implementing systems IMEI monitoring (for example, the ACR system in the Russian Federation), which in real time compare identifiers on the network with a database of legal devices. If duplicates are detected (when the same IMEI is used on two different phones at the same time) or “gray” numbers, the device is blocked at the tower level. Unblocking it after this will be extremely difficult.
It is also worth considering security risks. By downloading dubious utilities for changing IMEI from unverified forums, you risk infecting your PC or smartphone with malware. Many such apps contain Trojans that steal personal data or use the device for mining. Always scan your files with an antivirus and use only well-known open source tools or official utilities.
If your goal is simply to restore the network after a failure, proceed with caution and keep the original numbers. If you plan to use your phone to bypass locks, remember that modern technologies allow you to track the device even by other unique parameters (serial number, MAC address, hardware fingerprints), making changing IMEI an ineffective measure.
Is it possible to change IMEI without root access?
In 99% of cases, no. Access to the protected NVRAM partition requires superuser rights. There are rare exceptions for older models through the engineering menu, but on modern Android 10-14 this is almost impossible without unlocking the bootloader and getting Root.
Will the IMEI be reset after a system update?
If you wrote the number correctly into non-volatile memory (NVRAM), then the system update (OTA) should not overwrite it. However, if the update involves re-partitioning the disk or resetting the modem part, there is a risk of data loss. Always have the number written down at hand.
Does changing IMEI affect the warranty?
Yes, any intervention in the software that requires unlocking the bootloader or obtaining root access will automatically void the manufacturer's official warranty. The service center will easily determine the fact of software modification.
What is an IMEI “clone” and why is it dangerous?
Cloning is assigning the IMEI of another legal device to your phone. This is dangerous because when using the network you will “glow” under someone else’s number. If the owner of the original phone reports problems, the blocking may also affect your device.
How to find out if a phone is blocked by IMEI?
There are online services and operator databases where you can check the status of the device (stolen, pawned, clean) using the entered number. Before buying a used phone or before changing the procedure, always check the status of the original number.