Introduction Huawei USB modems, often branded as "E3531," "E3372," "E8278," or found inside mobile hotspots (MiFi) and older Android phones, use a USB Serial (Ser) driver to establish communication for diagnostics, firmware updates, network unlocking, or converting the device from "CD-ROM mode" to "modem mode."

If all else fails, the device may be hardware-limited (e.g., certain carrier-locked E3372s have no serial interface at all) – in which case you must reflash the firmware using a dedicated downloader tool. Last tested: Windows 11 24H2 / Huawei E3531 + E3372h-153

Huawei Data Card Driver for Windows (v11.210.04.00.00) or newer.