Here is mine. As you can see, its only 4G+. Will switch to 3G/H during calls. Already factory reset my phone after update, still nothing.You did the *#*#86583#*#* in the Phone Dialer and got 'VoLTE carrier check disabled' ... You wrote Enabled.. its supposed to be DISABLED.. then the option appears in SIM Card Settings. If this is not the fix for you then I dont know what it could be.. this worked for me.. I have a VoLTE symbol in the Status Bar near cell/wifi reception indicator.