I did activate/test a new T-Mobile (US) SIM card into Sony Xperia II, SIM card did work as 4G (VoLTE); and then transferred t to Sony Xperia III, and SIM card still connecting to 4G.
However, the 1st SIM card failed on Xperia II; and did replace the SIM card at T-Mobil Store (3rd card); and that failed too, with “denied” message under ‘Cellular network’ page at SailfishOS.
Any suggestions to overcome this VoLTE issue with Sony Xperia II and US T-Mobile?
Thanx
@X0X0 That’s very odd. It does sound like that IMEI is on a list /w T-Mobile. Can you run an IMEI check to make sure it’s not flagged as stolen, lost, salvaged or something? I can’t think of much else to try besides grabbing a US Mobile SIM and trying that T-Mobile MVNO. I largely expect the same problem though if the IMEI is on any of the “naughty” lists. Also, just to confirm, you’re using T-Mobile prepaid and a prepaid SIM, correct? Post paid accounts and SIMs won’t work. I don’t know why, but it’s purely account controls and nothing technical.
@robthebold Hum. X0X0 found something similar. That’s very odd, I have now three people with 10 II on T-Mobile prepaid and four on US Mobile. One question I might ask is if you’re using T-Mobile prepaid or a postpaid account. This will absolutely make a difference. If you’re using T-Mobile prepaid (and a prepaid SIM) then purely out of curiosity, can you request a free SIM kit from US Mobile (use checkout code FREESIM)? I’m curious if you can activate a basic account (like $12 I think) and get that to work. If it registers to US Mobile successfully then there might be something else to address with T-Mobile. If it’s denied on US Mobile also then it’s on a “naughty” list.
It’s T-Mobile Bring-your-own-device prepaid plan with a prepaid SIM.
Wikipedia says that US Mobile uses T-Mobile and Verizon – do you know which you’re getting when you sign up?
So I finally got Sailfish OS flashed on my Xperia 10 iii and, aside from MMS, everything else seems to be working great, including VoLTE.
I went into my MMS settings and set everything to 10.188.239.145, but still no dice.
I’m on T-Mobile US, specifically using their T-Mobile Connect $15/mo plan. Thoughts @hackman238 ?
For me on Xperia 10 III (62.0.A.3.109) it can’t even register.
Without config changes or even with: VoLTE on the Xperia 10 II - filling in the gaps - #57 by JacekJagosz
Registered: ✕ - fixed that with help from archon: VoLTE on the Xperia 10 II - filling in the gaps - #58 by archon
Country: PL
Provider: Polkomtel
Device model: 10 III
Registered: ✓
Voice in: ✓
Voice out: ✓
SMS in: ✓
SMS out: ✓
**** Requires modem.conf mapping. (only on X10II?)
And also requires sending an SMS to activate VoLTE service, as archon said.
Tried a few more times, to no avail. It looks that it is really impossible to have VoLTE activated on Tandem (twin SIM) offer in T-Mobile Poland. All customer support people say that it can’t be done, attempts to activate it via SMS or via their online portal result in various errors (e.g. “Not an USIM card” while it is an USIM card, or “Temporary error, try again later”).
Well… having those twin “Tandem” SIM cards is so convenient and useful that I will have to give up on VoLTE for now, i.e. for as long as voice calls can still work without it. But I still can’t comprehend how can they simultaneously offer two services incompatible with each other.
So for me:
Country: PL
Provider: T-Mobile Poland - Tandem (twin) SIM cards
Device model: 10 III
Registered: ✕ (because they refuse to activate the service at their end. The only solution is to switch to a normal, single SIM card and only then have the service activated).
If VoLTE can’t register (the switch keeps blinking forever, also the terminal-command shows not registered), this means that my provider (Country AT, provider HoT) probably doesn’t have VoLTE enabled, right? Should I add this to the Wiki then with everything marked as not working? Because it’s probably not really an issue from Sailfish
Thanks for sharing this info @NIS. If it’s useful for other users to know about, then I think it’s worth including independent of where the problem is. So I’d suggest to add it to the table anyway.
I tried a DNA/Finland SIM card in a X10II running 4.4.0.68, but it didn’t even show the VoLTE option. I’m not even sure if the SIM had VoLTE enabled. Should it show up nevertheless?
I had to do a manual config mapping before it registered.
Ok, I will add it then
Have a question guys: Could VoLTE could be switched on, while the SIM Card is in Roaming mode?
SE - TELIA on the Xperia 10 II shows that it registers. Voice in and out are OK. Sends and receives SMS. (S55.3)
I’m using the dual-SIM Xperia 10 II and I have Telia as a carrier in Sweden. I have successfully registered this phone for VOLTE, according to the “4G calling (beta)” light in the Mobile Network settings.
Like someone else wrote in the “filling in the gaps” thread, it’s important to set the mobile data to the SAME carrier as the voice calls carrier, even if you have mobile data turned off. When they were different, I got the blinking light in the settings.
I confirm the trick worked
Note though that I had to reboot twice as I could not call after the first one. Maybe I had to wait more but a second reboot worked anyway .
VOLTE is indeed a nice addition. A faster handling of phone calls and sms 
Country: NL
Provider: KPN
Device Model: 10 II
Date tested: 2022-08-03
Registered: ✓
Voice In: ✓
Voice Out: ✓
SMS in: ✓
SMS out: ✓
Works without additional configuration.
I don’t have to set primary data and voice carrier to be the same on my Xperia 10 II, having Fello (Telia) in primary and Telenor SE in secondary SIM slot. I can have Fello as primary voice operator and still register to VoLTE on Telenor on secondary.
I do have to set the operator I want as primary data carrier for it to register VoLTE though. The operator that isn’t used as data carrier wont register with VoLTE.
hello
Country: FR
Provider: B&YOU (from bouygues telecom)
Device Model: 10 III
Date tested: 2022-08-09 (for 2 weeks)
Registered: ✓
Voice In: ✓
Voice Out: ✓
SMS in: ✓
SMS out: ✓
but MMS doesn’t works with or without VoLTE using same parameters as Xperia X with same provider. if any idea ?
have a nice day