Question: how to restore qcn file?
Answer: Steps to Restore QCN/EFS on Qualcomm devices Download the QPST package and run “QFIL.exe” file. Make sure that the program is in “Lenovo HS-USB Diagnostics” mode. After this, you can restart your Qualcomm device and check whether the details have been restored or not. If not, then try the process again.