: Another application (like a terminal emulator or another flashing tool) may already be using the COM port.
This error is the bane of anyone trying to flash firmware on Qualcomm-based devices (Xiaomi, OnePlus, Motorola, LG, etc.) using .
Connect your device directly to the PC. Do not use external USB hubs or extensions. Conclusion
Use a USB 2.0 port rather than a USB 3.0 (blue) port. USB 3.0 ports often cause connectivity issues with older Qualcomm devices. qfil failed to open com port handle
Most users assume (A). Experienced engineers know it is almost always (B).
The device receives the packet, says “Wrong version,” and drops the connection. QFIL then reports “Failed to open COM port handle” retroactively because it closed the port in panic.
If the device boots to system or fastboot, use the command adb reboot edl or fastboot oem edl . : Another application (like a terminal emulator or
Long-press Power + Volume Up/Down until the device reboots, then manually re-enter EDL mode. Staying in EDL mode too long without activity can cause the port to "timeout" and fail the next handle request.
Another software background process is actively hijacking or monitoring the same COM port.
Windows often updates drivers automatically, which can break the specific QDLoader 9008 handshake required by QFIL. Do not use external USB hubs or extensions
If an ADB server is running in the background, it may contend for the device interface. Open your Command Prompt and type adb kill-server to shut it down.
Poor connection or using a USB 3.0 port instead of USB 2.0.