If steps 1–4 fail:

Sahara is extremely sensitive to voltage drops and timing. A poor-quality USB cable, a front-panel USB port, or a USB 3.0 port (which has additional pins) can introduce latency or noise, causing the "Hello" packet to be corrupted. USB hubs almost always cause this error.

Avoid using standalone QFIL downloads. Instead, download and install the complete QPST package and run the QFIL executable found in the C:\Program Files (x86)\Qualcomm\QPST\bin directory. 2. Clean Up File Paths