If your firmware is an OTA update.zip or in any flashable zip format then QFIL is not suited to flash firmware QFIL will only flash a firmware which is in Flat Build or Meta Build format.Do Not interrupt QFIL during flashing (till the flashing process is completed) or force-flash an incompatible firmware (bootloader) as this could result in a hard brick which would then require a USB Jig or JTAG to force the phone into Download Mode.The exact button combo for booting into EDL mode varies across Qualcomm devices so ensure to run a search around booting your model into EDL.
If you still have No Port Available after connecting the phone then its either the phone isn’t in EDL mode or you’ve not installed drivers for the phone.
Some roms / tools wipe or corrupt your EFS / QCN partition resulting in Null or Invalid IMEI, Baseband, Serial Number etc.
Step 2: Download and extract Qualcomm Flash Image Loader (QFIL) on your computer.
Step 1: Download and install Qualcomm USB Driver on your Computer(If you have already installed the Qualcomm USB Driver on your computer, skip this step).