To fix the error, diagnose the root cause first. The issue usually falls into one of four categories:
EDL.exe does not rely on the same buggy COM handle protocol. It writes raw bytes directly to the serial interface. qfil failed to open com port handle
If the driver is correct but QFIL still fails, something else is using the port. To fix the error, diagnose the root cause first
Even if the device appears in Device Manager, incorrect drivers can prevent QFIL from grabbing the handle. To fix the error