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Select or type the exact COM port number identified in the Device Manager.
[Tungtata] QCN Tool is a specialized freeware utility used to edit Qualcomm Calibration Network (QCN) files, primarily for repairing or changing IMEI numbers on Qualcomm-based Android devices. It is often distributed as a ZIP file (e.g., Tungtata QCN Tool.zip tungtata qcn toolzip
| Feature | Description | |---------|-------------| | | Dump current QCN to a .qcn or .bin file. | | QCN Restore | Write a previously saved QCN back to the device. | | IMEI Repair/Change | Modify NV items to rewrite IMEI (often for lost/stolen devices, or to bypass blacklists — illegal in many jurisdictions ). | | Null IMEI Fix | Restore QCN after a corrupt EFS partition (shows IMEI as 0 or null ). | | Signal/Network Unlock | Re-enable cellular bands after a bad flash or firmware update. |
| Tool Name | Target Chipset | Cost | Target User | Ease of Use | | :--- | :--- | :--- | :--- | :--- | | | Qualcomm | Free/Low | Advanced Users/Techs | Moderate | | Miracle Box / UMT | Qualcomm, MediaTek, etc. | Paid | Professional Repair Shops | High | | SN Writer | MediaTek (MTK) | Free | Advanced Users | Moderate-High | | Maui META | MediaTek (MTK) | Free | Advanced Users | High (Complex) | “Teach me
Verify that the computer registers the device under Windows Device Manager as a functional Qualcomm HS-USB Diagnostics COM port.
The phone's EFS partitions might be write-protected or securely locked. You may need to wipe the corrupted EFS partition first via TWRP recovery or a specialized fastboot command ( fastboot erase modemst1 , fastboot erase modemst2 ) before the tool can write new data. 3. Signal Stays "Searching" After Write | | QCN Restore | Write a previously
: The tool typically requires the device to be in "Diag Mode" to communicate with the PC.
Developed by a well-known developer in the Android customization community, this specialized tool simplifies the complex hexadecimal conversions required during network repair.
Enable on your phone (Settings > Developer Options > USB Debugging). Connect the phone to the PC.
For any tool to interact with your phone's modem data, you must expose its diagnostic serial port.