Originally Posted by flashcity90
s5 volte was made active on tmobile with there last base update to nf6. The alliance rom is based of tmobiles nf6 update. It is active in my city however my device is not the g900t but g900a just running the g900t rom. I know that the phones are extremely similar so i thought that volte should work. I did my searching and havent found anything helpful.
You may need to manually enable it, since you are using a 900A on TMB. And presumably not accepting TMB OTA updates.
Or alternately open a support ticket to confirm that your 900A is properly provisioned (active) for VoLTE.
You can search the forum (or my post history about 100 posts back) for details of how to find the setting in the service mode menu.