Thank you, Kyle. That is helpful.
Now I just have to figure out why the tool does not work.
On the other hand, calls work even though they are in 3G.
So, maybe it is better to wait for the appropriate update.
I just got my L5 last week, and this appears to work out of the box - T-Mobile with the BM818-A1 modem. Benefits of joining the party late, I guess. 35 down/10 up while on a phone call. 
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That doesnāt mean youāre making a VoLTE call. You really need to use the tool to query the modem to see what mode it is in. Like I said before when I make calls I see 4G but the call is using HSPA not VoLTE for the call itself.
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My phone is part of the same batch, so thatās probably not what makes the difference.
Well, I guess itās āclose enoughā for me š¤· I donāt see what the advantage is, assuming Iām not dropping out of 4G, and data works while the calls work.
Call setup speed and voice clarity will be better on VoLTE.
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If you are refering to I would like to replace PureOS with NixOS: Iāve done that.
I do not have sound in calls yet. When Iāve fixed that Iāll reply to the NixOS topic with instructions.
If you were refering to the update tool: Iāve got no clue as to what the name of the tool is yet.
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I was referring to NixOS.
If you have any prior communication about your process, I am interested.
Also interested Guix as well.
Iāve updated the NixOS topic: Can someone with serial console access try NixOS kernel on Librem 5?
Iāll create a dedicated topic on NixOS when Iāve solved the sound-in-calls issue.
Happy to answer any questions you have in the meantime. That will actually help building a new topic post.
Guix is als interesting indeed 
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Just to make sure, I entered the modem commands mentioned above (I used socat in stead of screen).
Result: zilch.
Do I need a firmware upgrade maybe?
Current version: MPSS.JO.2.0.2.c1.1-00032-9607_GENNS_PACK-1.351938.1
Thatās the version I have as well, looks like itās from Nov. 2020, so I too would be interested in knowing if this is the correct/newest firmware for the modem. I canāt get VoLTE to work so wondering if this is why.
VoLTE is to have both the call and the data be using VoLTE (4G). As raenrfm pointed out, itās
possible that your call is not 4G (e.g. HSPA).
You are right, that as long as you can call and use data simultaneously itās not
a big deal for you yet. But you should realize that some carriers ā¦ and, perhaps, some
local areas (when you traveling) might not allow 3G for calls now or at some later point.
And in that situation you will need VoLTE for calls.
Try using socat instead of screen.
The first line would then become: sudo socat - /dev/ttyUSB3,ctrl
The rest stays the same.
Using screen or socat doesnāt work for me as itās not finding those commands.
doing āsudo /usr/bin/bm818-volte onā works tho.
I see all kinds of things happening in the journalctl -f --system terminal window when I do it.
Screen and socat need to be installed before you can run them.
Having said that: I tried every method mentioned here and elsewhere - including āsudo /usr/bin/bm818-volte onā - without any result.
I just canāt enable VoLTE on my L5. It keeps dropping to 3G when making a call.
I have the same experience except my call is an LTE call just not VoLTE, but that could be peculiar to my network and how they handle voice calls. I know (I work for the company just not in the wireless devision), that if there is a non VoLTE capable phone that is LTE capable then the call is handled via HSPA which is 4G so I think that is my case. Either way for both of us, no matter what we do VoLTE isnāt working. I confirmed that VoLTE is enabled on my sim, I called customer service specifically to make this request and we have way better customer service than the big carriers in Canadaā¦lol.
I thought Iād double check whether T-mobile really has enabled VoLTE on my connection. They have. So, the problem is with the modem and/or the firmware.
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I also wonder what the problem is with t-mobile.
unfortunately, the support from t-mobile was a joke.
Hello,
I received my Librem5 last year. I live in Europe and my provider is Telekom. When I check my providerās config, VoLTE is enabled. As I read above, maybe there is a problem with Telekomā¦reagrdless I tried to enable VoLTE and here is my story:
I regulary update my system with
sudo apt update && sudo apt full-upgrade
sudo reboot
I currently run byzantium and kernel 6.1.0-1-librem5 (manually installed by sudo apt install linux-image-6.1.0-1-librem5).
Today I installed bm818-tool using apt. After installation I reboot my system and start the gui tool. In that tool I opt-in VoLTE enabled and reboot again. Afterwards I startet a call to my home and checked wit the gui tool for VoLTE but nothing happens.
On the top under FW version it is written:
M100E_YCSN0_1.0.0_210122
YCSN0_M100E_1BAD_3117_V1.0.0.1_20210906
M100E_1.0.4_200715
So, IMO VoLTE donāt work for me. Do I have to update my firmware as mentioned above? If the update process ist still critical, I will wait until there is an official and save way to do the update. @Purism whatās the current state?
Other question:
What means CBS enbale in the bm818 tool?
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CBS I think is Cellular Broadcast Service so I think that enables alerts on your phone. You know the oneās that wake you up at 3am.
I have the same experience, no combination of using the tool or command line has enabled VoLTE for me but also my Samsung S22 which is VoLTE capable and enabled isnāt using it for some reason, I have to enquire more with our wireless engineers why that isnāt working.