Updating the Huawei Y6 (SCL-U31) via an SD card is a common method to fix software issues like bootloops, "hang on logo" errors, or to manually upgrade the system
Here is a comprehensive breakdown of how firmware works on this device and how to manage SD card operations. Huawei Scl-u31 Firmware Sd Card
the file to a /dload/ folder on a formatted Micro SD card. Updating the Huawei Y6 (SCL-U31) via an SD