Do not cross‑flash firmware between different hardware sub‑models (e.g., B660s-2 vs B660s-23). The baseband firmware differs.
Most B660 units are white-labeled for specific carriers (T-Mobile, Telstra, Vodafone, Optus, etc.). huawei b660 firmware
Huawei maintains a community forum where engineers occasionally post updates. huawei b660 firmware
