Flash Only System.img and wipe from recovery
TAG-AL00C92B170_Firmware_China_Nonspecific_Android 5.1_EMUI 3.1_05021VAE.zip
TAG-AL00C92B168_Firmware_China_Nonspecific_Android 5.1_EMUI 3.1_05021VAE(FULL).rar
TAG-AL00C92B167_Firmware_China_Nonspecific_Android 5.1_EMUI 3.1_05021VAE.zip