Hi guys, I just purchased a few days ago a S9, model SM-960F, from a french seller of eBay. The cellphone came with french firmware, listed on Sammobile site as XEF/XEF/XEF, with september security patch. Everything is working fine (calls and internet), except for VoLTE and VoWIFI. By the way, I live in Brazil and my carrier (VIVO) does provide VoLTE in my region, which I confirmed when I inserted my simcard in my wife´s phone (S10e).
Another point is that it is available in the network settings menu the switch panel that turns on/off VoLTE. My question is: is there any procedure that can be taken by myself in order to make them work, here in my country?