Wait 5–10 minutes. Do not disconnect. Once you see a green checkmark – you are done.
The Huawei TRT-L21A is a mid-range smartphone (often sold as the Huawei GR3 2017 or Honor 6A in some regions). It is powered by the MediaTek MT6737T processor. Like many Huawei devices, it uses a custom encryption system that can trigger a “password required” screen following a failed OTA update, factory reset attempt, or malware attack. huawei trt-l21a flash file without password