1. Have your boom! Mobile friendly enable HD Voice (VoLTE)
2. Input the boom! RED APN settings.
3. Open the dialpad and enter *#*#4636#*#* (the numbers spell INFO on the T9 pad) which triggers the phone's diagnostics screen to rise to the foreground. In the section labeled Phone Options, toggle the Advanced LTE Capabilities setting to On,
4. Press the home button to return to the phone's desktop. After two successful software-trigged power cycles (holding the power key and selecting Shut down in the power menu, then holding the key again to power the phone back on, then repeating both steps)
5. Open the Settings app and look for a new option for Advanced Calling Features in the Network section
6. Toggle on Advanced calling