Public Mobile (Canada): failure to configure VoLTE

[digdis]

I'm having an issue where my PinePhone can use the 4G network for data and SMS/MMS (in/out), but I'm unable to hold a call on the 4G network. Currently the call immediately degrades to the 3G network, and if I force exclusive usage of the 4G network, my calls fail to connect entirely.

Here's my current setup:
PinePhone v1.2b Beta Edition
postmarketOS (systemd; edge release) -- Phosh UI
calls 48.2 (GNOME)
default firmware for the Quectel EG25-G modem (I've not yet tried https://github.com/the-modem-distro/pinephone_modem_sdk).

network: Public Mobile (Canadian subsidiary of TELUS)

I've been following https://pine64.org/documentation/PinePhone/Modem/ to attempt to set up VoLTE.

Using the default profile ROW_Generic_3GPP and subsequently trying the profile Telus-Commercial_DO, I've sent AT commands in this way:

Code:

echo 'AT+<command here>' | sudo atinout - /dev/ttyUSB2 -

When I enable IMS, I get the okay:

Code:

AT+QCFG="ims",1

Code:

OK

However, after restarting the modem with AT+CFUN=1,1 I am unable to place a call, just as before. Indeed, when I query the IMS status, I'm told that VoLTE is disabled:

Code:

AT+QCFG="ims"

Code:

+QCFG: "ims",1,0

OK

I've also tried to enable VoLTE following https://quectel.com/content/uploads/2024...l_V1.0.pdf

Code:

AT+QCFG="volte_disable",0

Code:

OK

But the issue still persists following a modem restart.

Does anyone have experience in getting VoLTE to function with this carrier or in a similar situation? I'm unsure whether I'll have to change carriers altogether.