It looks like you're asking about a security or forensic analysis paper (or you're planning to write one) on the file msm8x39downloadtool.exe.
The tool will usually verify the integrity of the firmware files automatically. msm8x39downloadtool.exe
Completion: A green "USB Download Completed" message indicates the process is finished, after which the device can be rebooted. Security & Safety Notes It looks like you're asking about a security
Drivers: Install necessary Qualcomm USB drivers. You may need to disable Driver Signature Enforcement on Windows 8 or 10. msm8x39downloadtool.exe