Introduction The China Mobile M654 is a popular, budget-friendly 4G LTE USB modem (often referred to as a "dongle" or "data card"). Widely distributed by China Mobile and its resellers, this device provides a simple way to add internet connectivity to laptops, desktop PCs, and even some embedded systems via a standard USB port. However, like any piece of networking hardware, its performance, stability, and security depend heavily on its firmware.