Huawei does not provide a centralized public firmware repository for consumer CPEs. Instead, updates are distributed via:
Some users report that if updates aren't appearing, inserting a SIM card from a different major carrier can sometimes trigger a "pending" update from the Huawei servers. huawei h122-373 firmware
This is the most direct way to check for and install updates from a computer. Huawei does not provide a centralized public firmware