For most modern Qualcomm devices (Snapdragon 855 and newer), newer driver versions or the built‑in Windows serial driver may suffice, but for legacy hardware or specialized diagnostics, v2.0.3.9 remains a trusted fallback. Disclaimer: Modifying smartphone firmware, repairing IMEI, or using diagnostic ports may void warranties, violate local laws, or permanently damage your device. Proceed at your own risk.