How to Backup & Restore QCN on Qualcomm Devices

Did you suddenly lose the IMEI number of your smartphone? Does your WiFi address or Bluetooth get null? Well, if these happen to your phone, then do not panic. It occurs from time to time, and we have a better solution for you. You can back up these files and restore them later when you lose them. This post will share the complete guidelines about how to backup and restore QCN/EFS files on your Qualcomm smartphones and tablets.

We want to notify that you can apply these methods on only Qualcomm powered smartphone and tablets. Also, you will need to download the QPST flash tool to backup and restore these files. If you have not downloaded this tool yet, check out another guide on download the QPST Flash Tool’s latest version. This post discussed all details on how to download and install this flash tool on your PC. Now, let’s check out what it is and how to back and restore these files.

What are QCN/EFS Files on Qualcomm Powered Devices?

QCN is the abbreviation of Qualcomm Calibration Network. It is a built-in file you can find in all high-end and flagship smartphone models, including the Samsung Galaxy series. QCN file is an important and sensitive file of the device network. It is hidden in the deepest core of the Qualcomm powered smartphone’s internal memory file system. The EFS (Encrypted File System) or particular partition dedicated folder stores all sensitive information such as IMEI and baseband numbers of your device.

When is the QCN/EFS File Needed?

When your device’s EFS file is erased, wiped, phone calibration erased, and the phone does not see the network/ not see 3G/2G/LTE network, you need to write or restore the QCN file to repair these issues.

Which Smartphones support QCN File Writing/Reading?

All smartphones and tablets powered by Qualcomm Snapdragon SoC support QCN file; especially, all Samsung Galaxy smartphones and the latest flagship device that uses Snapdragon chipset is compatible with writing and reading the QCN file.

How to Backup QCN/EFS File in Qualcomm Devices

If there is a chance of losing the IMEI number, WiFi address, and Bluetooth keys, you have to back up this info, the QCN file on the Qualcomm device. To do that, you need to use the QPST tool. Now, follow these steps below to back up the QCN file.

Step 1: Download QPST Tool and install the “QFIL.exe” file. However, make sure that this flash tool is in “Lenovo HS-USB Diagnostics” mode.

Step 2: In the dashboard, go to the “QFIL” and choose the “Tools” option and then select the “QCN Backup Restore” option.

Step 3: When the new window opens, click on the “Backup QCN” option and wait to complete the backup process. After having the backup of the QCN file, you will see the following info.

  • Start Download QCN
  • COM Port number:7
  • Checking if the phone is connected…
  • Is PhoneConnected: Passed. Phone is connected
  • Sent SPC code to the phone successfully
  • Downloading QCN file : C:\temp\00000000.qcn
  • Done downloading the qcn file: C:\temp\00000000.qcn
  • Finish Backup QCN

How to Restore QCN/EFS File on Qualcomm Device

In the above section, we have explained how to backup the QCN file on a Snapdragon smartphone. If you already took backup using the QPST tool, you can restore the same file by following the steps below.

Step 1: Download the QPST flash tool and install the “QFIL.exe” file. However, make sure that this flash tool is in “Lenovo HS-USB Diagnostics” mode.

Step 2: In the dashboard, go to the “QFIL” and choose the “Tools” option and then select the “QCN Backup Restore” option.

Step 3: When the new window opens, click on the “Browse” button and locate the file named “00000000.qcn,” and click on the “Open” option.

Step 4: Now, click on the “Restore QCN” option and wait to complete the restoring process. After restoring the QCN file, you will see the following info.

  • Process Index:0
  • Start Restore QCN
  • COM Port number:7
  • Uploading QCN file : C:\temp\00000000.qcn
  • Checking if the phone is connected…
  • Done uploading the QCN file: C:\temp\00000000.qcn
  • Finish Restore QCN

When you see this info on your device, you can restart your Qualcomm smartphone and check whether all device info is restored or not. If you follow these guides correctly, the information should be restored. However, if you cannot see the details, then follow the steps again.

That’s it, guys. This is how you can backup and restore the QCN/EFS file on Qualcomm smartphones and tablets. As we have mentioned earlier, the QCN file contains sensitive device information. So we recommend keeping this info secure. Of course, feel free to comment below if you have any queries.

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