Write oem file wich included in the File And Flash This Firmware In Upgrade Mode
STK-L21ALAS 10.0.0.323(C185E6R6P1)_Firmware_EMUI10.0.0_05016LQE
After flash follow this (https://www.youtube.com/watch?v=nKYrGMhx5hc&t=2s)
STK-L21ALAS 10.0.0.193(C185E3R6P1)_Firmware_EMUI10.0.0_05015XSC