: Try a different USB port—preferably a USB 2.0 port on the back of the motherboard if using a PC—and use the original or a high-quality data cable.
: Open Windows Device Manager and check under "Ports (COM & LPT)." The device must be listed exactly as "Qualcomm HS-USB QDLoader 9008" . If it shows "Qualcomm HS-USB Diagnostics" or any other name, QFIL will fail to open the handle. Reinstall/Update Drivers :
on your motherboard (back of the PC) rather than a front-panel port or USB hub, which can cause power fluctuations. Try a Different Cable
If the port opens but immediately fails, it is often a protocol error.