Ensure your model is exactly the HG8145V5. Applying firmware for a different model will cause system failure.
If you are updating primarily for better performance or features, consider placing the HG8145V5 in and using your own powerful router (e.g., Asus, Ubiquiti, MikroTik). This bypasses most firmware limitations while retaining the Huawei as a pure GPON modem. No firmware update needed – and it is much safer. Huawei Router Hg8145v5 Firmware Update