Multiple users on Reddit’s ROG Phone 3 subreddit have corroborated that VoLTE starts working on AT&T after installing the latest update. The OTA is good for T-Mobile users too, as our Editor-in-Chief, Mishaal Rahman, has confirmed that the phone can now make use of VoLTE on T-Mobile without any extra configuration. This is no doubt an important advancement as more carriers move towards adopting VoLTE on their network.
For your information, it is possible to manually set the carrier-specific parameters on select ASUS smartphones — including the ROG Phone 3 — to unlock advanced IMS services like VoLTE on T-Mobile’s network if you have root access. Having said that, an official update is always preferable in this scenario, especially since not everyone wants to tinker with their shiny new gadget.
At the time of writing this article, the official announcement thread for this update is no longer up on ASUS’ ZenTalk Community. Perhaps the current implementation needs another coat of paint before ASUS is confident enough to announce it officially. If you want to sideload the new build anyway, you can download the full firmware from the link below.
To install, simply place the downloaded file in the root directory on your ROG Phone 3. Then reboot your phone and check for the firmware update notification pop-up on the status bar. Tap “System update file detected” and follow the steps shown to update the firmware.