Before any firmware operation, use Huawei Multi-Tool (by Team MT) to backup the modem , cust , and oeminfo partitions – these contain the unique C636 identifiers. Losing them without a full flash package can permanently turn your STK-L22 into a brick. Note: As of 2026, Huawei has largely stopped OTA support for the Kirin 980 series. The last official C636 firmware remains on the Huawei servers but may require HiSuite Proxy to access.