Thanks for this update - did you test with the bm818 tool? because it doesnt look like the phosh indicator is always up-to-date?
I have a second pre-paid sim with amaysim (Optus) that I might test with also.
Im fairly sure that volte was working with my boost / telstra sim on the pinephone previously, so seems strange that it then would not work with this modem.
No, m8. I just, you know, made a phone call and looked at the top line. 
Remember that a reboot may be needed in order to get everything to recognise that you have enabled VoLTE after doing so.
I’ve had the same experience as you (my phone is in with repair rn so I haven’t tried it since before Christmas). Same thing, latest firmware, enabled VoLTE, confirmed with my carrier that my account had it enabled (works on an android phone) and I have never gotten it to work. Voice calls remain HSPA. Sounds like your network and Rogers here in Canada might be using the same gear perhaps. Obviously there is something in the modem firmware that isn’t negotiating the VoLTE part correctly for us for some reason. Maybe we’ll get a 5G modem soon…lol.
Ok - so i had some time to try different sims.
I had access to 3:
Boost (Telstra)
Amaysim (Optus)
TPG (Vodafone)
The only one I could get VoLTE working with was the TPG/Vodafone one, which is unfortunate because it has by far the worst coverage. The Boost / Telstra SIM is by far the best experience - although I don’t know how much of that relates to where I was testing. Amaysim / Optus was absolutely horrible - by far the worst. The phosh modem status just looped between Amaysim and “Cellular” constantly and I was unable to make a call or use data.
I had the same issue with modem firmware and an update has made it work on Vodafone in Australia (this thread)
I was able to get access to a Telsta sim so I tried that as well and calls do not work and bm818-tool reports it drops to UMTS while the call is active.
I’m not sure this is something that is possible…
Reading things like this https://forums.whirlpool.net.au/archive/9m01z7np it seems that we need to install a MBN file on the modem.
Page 53 of this Quectel documentation includes a AT command to 4.4.1. AT+QMBNCFG="List" Query Imported MBN File List. They even mention Telstra
That command doesn’t work on my BM818. So I’m assuming that not all Quectel modems support it.
According to this post there is a full list of AT commands available. There is no mention of MBN, Telstra or VoLTE there.
EDIT: Not all of the commands listed in https://www.waveshare.net/w/upload/6/68/SIM7500_SIM7600_Series_AT_Command_Manual_V2.00.pdf pointed to from Using AT commands and commandline to do stuff work either. So it seems that isn’t the correct list. Maybe someone from Purism has a list of AT commands?
So unless somone can figure out a way to add extra MBNs, update the firmware or replace the modem we might all need to switch to Vodafone or switch phones
The Librem 5 doesn’t have a Quectel modem in it. (The PinePhone does however.)
Unfortunately at the more niche end of modem function, different modems use all sorts of proprietary / non-standard AT commands. On top of that, some modems will have undocumented AT commands. On top of that, the host computer may be using e.g. QMI instead of AT commands (but you can still use AT commands to do whatever AT commands can do).
I would think that the modem manufacturer (Broadmobi) needs to provide more info in order to move this forward.
I have a few updates on getting this working.
According to 4G VoLTE calls confirmed working with carrier x the PinePhone works with Telstra and VoLTE. I did a test today and my PinePhone seemed to stay connected to the LTE network during the call (although audio didn’t work).
The post Quectel EM12-G WWAN 4G Modem on Librem 5 also did some testing on using a Quectel EM12-G in the Librem 5.
The Quectel EM12-G is similar to what is in the PinePhone (the actual PinePhone EG25 modem looks to be too large for the Librem 5). The Quectel EM12-G datasheet indicates that it is compatible with Telstra as well
So I’m hoping that something like this could be swapped out in the Librem 5 and then used to get VoLTE.
There are some challenges with swapping the modem:
Thanks for the heads up. I’ll try to be extra gentle. I’m a little surprised the connectors are so brittle. I use u.FL connectors for other things and have never had any issues.
I have swapped the WiFi cards before and I had trouble with the lengths, but hopefully the two cards are similar enough that it will work.
Yeah, the config changes are the hard part. I’m hoping it isn’t too hard as the modem should be similar to the one in the PinePhone which is generally well supported.
Considering the issues with the modem on the Librem5 (Mobile data stops working, outgoing packets still sent but incoming packets no longer arrive (#328) · Issues · Librem5 / OS-issues · GitLab) I’m also hoping this might help.
Realistically though, there isn’t much choice. We (as in Librem5 users) need to either find a VoLTE solution or we are limited to Vodafone only in Australia. Even then as more 3G networks worldwide get switched off this is only going to get worse and worse.
I was one of those that managed to pop off the u.fl on my modem when doing the procedure to replace the WiFi card. I looked at the modem afterwards and it really looked to me like a cold solder joint on the u.fl. I know they are only meant for around 10 cycles or so but not half a cycle. In hindsight maybe I should have applied the tip of my soldering iron to it before I removed the cable…lol.
Until recently, I was unable to get VoLTE going with the L5 on Optus in Australia. Optus advised that technically there was no reason from their end why it should not work, so I went back to Purism support, requested and received the instructions for updating the modem bm818 firmware, and since the update, VoLTE has worked just fine. Though I am getting a new behaviour: whilst the incoming voice is very clear, it occasionally cuts out and I lose a few words before it cuts back in. I don’t recall this happening before under 3G, but for the moment I am blaming this on the caller’s handset …
Would you be able to report here what modem firmware version you are now running?
The phone was originally delivered with (according to the BM818 tool):
M100E_YCSN0_1.0.0_210830
YCSN0_M100E_1CMD_B227_V1.0.0.1_20210907
M100E_1.0.4_200715
After the firmware update, it is now
M100E_YCSN0_1.0.0_220926
YCSN0_M100E_1CMD_B227_V1.0.0.2_20220930
M100E_1.0.4_200715
Firmware needed a couple manual power offs and restarts to kick in.
One of the Optus support pages indicated that Optus may need to enable VoLTE for your account. When I contacted them they indicated that it was already enabled (at their end) for mine. Just saying; in case the firmware update doesn’t work, check with Optus to see if the switch is off for your account. Optus were very professional and supportive at all points, and the phone (L5) and modem (BM818) being new to them was not an issue.
That’s interesting. I have VoLTE enabled on my account and also with the BM-818 tool and still cannot get a VoLTE call to happen.
M100E_YCSN0_1.0.0_220926
YCSN0_M100E_1ACD_B325_V1.0.0.2_20220930
M100E_1.0.4_200715
This is my modem firmware, slightly different than yours.
I’m not sure of the meaning of the ‘1CMD_B227’ -vs- ‘1ACD_B325’ difference, but these strings appear in other posts here so not a serial number, and didn’t change when I upgraded firmware so not firmware version. Maybe related to the modem variant (E1/A1/T1)? Mine is T1, what is yours, and are we still talking Australia here?
Sorry I’m in Canada, but my VoLTE isn’t working either so just trying to see if there is any commonality between our countries. When you make a call is it defaulting to HSPA?
When making calls the L5 used to drop from 4G to 3G and the BM818 tool would show HSPA. Once the call had ended, the indicator would return to 4G. Since the firmware update it stays on 4G and the tool shows either ‘FDD LTE’ or more commonly ‘TDD LTE’ during calls.
Hi @alistair23 Newbie here doing as much reading as I can before choosing my next phone. Am happy enough with Vodafone here in Perth. And interested how VoLTE experience is holding up? Is it stable enough for a daily driver?