STK-L21M 10.0.0 (C185) Reset Frp (Flashing By SD) by newfirmwares.com
After flash follow this https://www.youtube.com/watch?v=gvwryb-HCI8
Huawei Y9 Prime ( STK L21M
After flash follow this https://www.youtube.com/watch?v=gvwryb-HCI8