[操作疑難] flash 左 ROM, 可唔可以繼續用香港 VoLTE

LG g3 單卡 D855,

flash 左 XDA G3 stock based ROM, 無左 VoLTE,  

ROM 有support VoLTE, 有 setting係到, 但係唔 work,

應該係香港 VoLTE set D野唔同, 有冇得整整??

Thanks Chings