VoLTE on the Xperia 10 II - filling in the gaps

They did ask for phone model, and did not say it should not work…

I’ll try another config soon, too.

Hi Andrew

Thanks for the guide. It worked for me.

getprop persist.vendor.somc.cust.modem0 returned S20.1

There was no directory called this.

I found a config for EE in UK on the phone


I made the missing directory - mkdir /vendor/oem/modem-config/S20.1

and added modem.conf file with the contents


Now showing as VoLTE registered.


It should be modem.conf file.

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It looks like a conf for S77.2 already exists, thus this is another issue entirely? How can we help with that? Did someone already contact O2 (Germany only?)?

Which modem config path does it point to? Is it correct?

I have virtual operator Fello (https://www.fello.se), which uses Telia’s network, but I get no id. How can I solve this?

In secondary slot I have Telenor SE (S58.1), but haven’t had any luck in register to VoLTE there.

Both operators support VoLTE according to their information.

Edit: and looking at operator support (VoLTE provider support) Fello is supported on the Xperia 10 III, so there has to be something I can do to fix this :slight_smile:

Thanks, li fixed it he typo

It links to …/de/… But only …/cz/… available. (is there a nice way to copy something from the terminal?)

I tested with Three UK. For anyone else using or thinking about going with Three, on the Xperia 10 III it worked immediately, but on the 10 II it required a modem.conf mapping:

mkdir -p /vendor/oem/modem-config/S21.1
echo -n "mcfg_sw/generic/euro/hutch/vlvw/uk/mcfg_sw.mbn" >> /vendor/oem/modem-config/S21.1/modem.conf

After doing this, calls and SMS messages work nicely on 4G.


Ok, this is a lot harder. There’s a big XML file mapping all of the MCC and MNC ids to those config IDs that you can find in /usr/share/sony-modem-switcher/service_provider_sim_configs.xml. I’m not entirely sure where you get those two values from, but I think they can be coaxed out of ofono somehow. Then I reckon mcfg_sw/generic/euro/telia/vlvw/swe/mcfg_sw.mbn might be what you need. Telenor already seems to be configured correctly, but I guess you could try it in the other slot?

Ok, I used to have access to a modem with AT-interface, where I could find out those numbers, but unfortunately I don’t have that currently. But at least I now know what I’m looking for. When I found them out, how do I know what “S”-number to map it to?

And I’ll try to swap the Telenor SIM to another slot to see if that works better.

Yeah the S id is a pain. I think I found some other similar files on Github. Might have some extra entries, especially in more recent versions.

Edit: if you do dbus-send --system --print-reply --type=method_call --dest=org.ofono /ril_0 org.nemomobile.ofono.SimInfo.GetSubscriberIdentity then the MCC should be the first three digits, and the MNC (MCRN??) the second two. I think.

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Yes, seems correct, but looking at the numbers the Fello use are Telia’s (“240 01”), so it should work out of the box.

[root@Xperia10II-DualSIM defaultuser]# dbus-send --system --print-reply --type=method_call --dest=org.ofono /ril_0 org.nemomobile.ofono.SimInfo.GetSubscriberIdentity
method return time=1657973867.099315 sender=:1.12 -> destination=:1.610 serial=4713 reply_serial=2
string "24001XXXXXXXXXX"
[root@Xperia10II-DualSIM defaultuser]# dbus-send --system --print-reply --type=method_call --dest=org.ofono /ril_1 org.nemomobile.ofono.SimInfo.GetSubscriberIdentity
method return time=1657973893.461479 sender=:1.12 -> destination=:1.611 serial=4717 reply_serial=2
string "24008YYYYYYYYYY"

Wonder why I don’t get an S number for my Fello SIM.

okay, I don’t know what I found earlier, but the diagnose, that there is only configuration for tef_o2/cz seemed to be wrong.

All files are apparently there, but it is still not working yet:

$ ls /vendor/firmware_mnt/image/modem_pr/mcfg/configs/mcfg_sw/generic/euro/tef_o2/vlvw/de/
mcfg_sw.mbn  -lah
-r--r-----    1 system   system     45.0K Mar 30  2021 /vendor/firmware_mnt/image/modem_pr/mcfg/configs/mcfg_sw/generic/euro/tef_o2/vlvw/de/mcfg_sw.mbn
$ cat /vendor/oem/modem-config/S77.2/modem.conf

Edit: Netmon shows its working now… (after a reboot, including hard reset with power+vol up). Doesnt work when i call my mailbox however


I have done some more testing.

After switching cards (primary/secondary) both SIMs (Fello&Telenor) works with VoLTE, as long it’s the card selected to be used for mobile internet connection. I guess it’s due only one modem is able to connect to LTE at the same time?

When primary SIM is used for internet:

When secondary SIM is used for internet:

Both screenshots above are with Fello in primary and Telenor in secondary slot.

The strange thing is that my Fello SIM gets (retains?) the same S-number as the Telenor SIM, but VoLTE works anyway. This behavior remains no matter which slot each SIM is in.


I have Fello Sweden and same problem as Mohjive (but with only 1 SIM card).

I think the sp line in the switcher config is a filter that only matches Telia.
And indeed after removing the line and rebooting, VoLTE registers and works for me.

--- service_provider_sim_configs.xml.ORIG
+++ service_provider_sim_configs.xml
@@ -297,7 +297,6 @@
   <service_provider_sim_config sim_config_id="S54.1">
-    <sp>Telia</sp>
   <service_provider_sim_config sim_config_id="S55.3">

edit: this will collide with the halebop config, which also shares the same mmc and mnc. The correct fix would be to allocate a new S-number and create a new config for Fello.


Good info. Though should there be new S-numbers allocated or should Telia, Halebop and Fello use the same ( and Tre and Hallon, Tele2 and Comviq, Telenor and Vimla etc)?

I don’t think everything in Sweden can be merged, I found four different modem configs in “swe” directories, and their checksums are different (hutch is probably Tre):

43be0f8b354d35a034403d034d1797e7  /vendor/firmware_mnt/image/modem_pr/mcfg/configs/mcfg_sw/generic/euro/hutch/vlvw/swe/mcfg_sw.mbn
a7228cdfb669c71341971b9a8032cf95  /vendor/firmware_mnt/image/modem_pr/mcfg/configs/mcfg_sw/generic/euro/tele2/vlvw/swe/mcfg_sw.mbn
4fff8c8393b75734e5f1bec6c3a3997a  /vendor/firmware_mnt/image/modem_pr/mcfg/configs/mcfg_sw/generic/euro/telenor/vlvw/swe/mcfg_sw.mbn
aba38f3ea22de0d299fba6006a69f24b  /vendor/firmware_mnt/image/modem_pr/mcfg/configs/mcfg_sw/generic/euro/telia/vlvw/swe/mcfg_sw.mbn

But unless this file is used for other things, there can probably be some consolidation.

I think the file has been generated by this script, from the original firmware:


Looks like Halebop already has one in some later version:

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Telia and halebop is already in the Sailfish file with mcc 240 and mnc 01. But we need something defined for Fello, which also shares mcc 240 and mnc 01.

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