The process varies slightly by brand (Huawei, ZTE, Netgear, Quectel, Sierra Wireless), but the general path is similar:
Your 4G LTE WiFi modem is a powerful computer with a radio attached. The stock firmware it shipped with was likely outdated the day you bought it, filled with carrier restrictions and known bugs.
: Ensures the modem can connect to specific frequency bands (e.g., Band 2, 4, 12) and supports features like LTE-A (Advanced) or 3G fallback Connection Optimization