Galaxy s20+ no wi-fi calling option

[swchance]

Hi, I purchased this phone from ebay. They said it was unlocked and would work with t-mobile, Verizon (my carrier) etc. Everything works fine but there is no option to enable wi-fi calling. I've contacted both Samsung & Verizon, both clueless as to why. The seller won't refund or exchange it, and ebay bots are bull_____. I live 15 miles from the closest cell signal, so starlink is it. Wi-fi calling worked on both my s10 & ulefon using the same sim. I've had the same phone number for over 35 years but now only works when I go to town. I can't afford another phone right now and could use your guys help.

Model: sm-g986u1

Service provider software version:
Tmb/tmb, tmb/vzw

Whatever the hell that means. I believe t-mobile & Verizon? Also hs audio is grayed out under developer options. Prior to this last android update wi-fi calling showed up in permission under phone, now its gone. Hmmmm.

 

[Zain Shahid]

I'm sorry to hear about the issues you're experiencing with your phone. Based on the information you've provided, it seems that your phone is not allowing you to enable Wi-Fi calling, which is causing you difficulties in areas with poor cell reception. You've contacted both Samsung and Verizon, but neither has been able to provide you with a solution.

It's also unfortunate that the seller won't refund or exchange the phone, and that you're unable to afford another phone at this time. However, there are a few things you can try to troubleshoot the issue with Wi-Fi calling.

First, make sure that Wi-Fi calling is actually supported by your phone model and carrier. Some older or budget phones may not have this feature, and certain carriers may not support Wi-Fi calling on all phone models.

Next, try resetting your network settings and restarting your phone. This can sometimes help to resolve issues with connectivity and settings.

If the above steps don't work, you may want to try contacting your carrier again and asking to speak with a higher-level support representative who may be able to assist you further. Alternatively, you could try visiting a physical store location for your carrier and speaking with someone in person.

Finally, if none of these options work, you may want to consider reaching out to a third-party repair shop or technician who may be able to diagnose and fix the issue.

I hope this information helps, and I wish you the best of luck in resolving the issue with your phone.

 

[B. Diddy]

Welcome to Android Central! That's a frustrating situation. When you talk about eBay bots, are you talking about this? pages.ebay.com/ml/en-us/coverage/BuyerProtectionForBuyers.html

 

[mustang7757]

Unlock version Samsung with Verizon sim should have Wi-Fi calling , where you looking for WiFi?
If it's not there then flash to the carrier version see if it's available.

Sent from my SM-S918U1 using AC Forums mobile app

 

[swchance]

Thank you for your reply. Yes, wi-fi calling is supported by my carrier (Verizon) and my model of phone (Galaxy s20+). I've reset my network settings and even did a factory reset, nothing. The closest town of any size is over 50 miles. The Verizon store does no repairs, and the independant repair shops don't have terrible reviews; 90 day turnaround times.

I'll contact Verizon again about speaking to someone in tech support at the next level. I think that may have already happened though.

Don't know why, but I feel that whoevers version of android this is had this feature removed (blacked-out) for what ever reason.

Should Verizon tech support not pan out, I thought of looking into updating the os with another version. It seems similar to updating a pc's BIOS or when I used to jailbreak my iPhone back in the day.

Before I go this route I'd appreciate someone (if), I was hoping if anyone knew if it's feasible on this version of phone. And lend some advice as to what different version might would accomplish this. Left on my own I'd probably brick the darmn thing. Qwerty

As far as bots on ebay go, every move I made to either exchange or return fhe phone was met with some stock canned solution sending me around and around in an endless loop, including buyer protection.

Thanks again guys

 

[swchance]

Thank you for responding mustang7757. Yes, im looking for wi-fi calling. Which carrier version would i need? Which carrier? If I understand it right the service provider software version tells something about this. Unfortunately I'm not knowledged in deciphering this.

tmb/tmb, tmb/vzw.

My guess is it references T-mobile and Verizon? Beyond that I haven't a clue. If that's even correct.

 

[mustang7757]

Thank you for responding mustang7757. Yes, im looking for wi-fi calling. Which carrier version would i need? Which carrier? If I understand it right the service provider software version tells something about this. Unfortunately I'm not knowledged in deciphering this.

tmb/tmb, tmb/vzw.

My guess is it references T-mobile and Verizon? Beyond that I haven't a clue. If that's even correct.

Tmb/Tmb/tmb/vzw means it's originally Verizon phone with TMobile esim or sim ?

Sent from my SM-S918U1 using Tapatalk

 

[mustang7757]

Model: sm-g986u1 this model number is carrier free /bloat free Samsung version firmware

If it was Model: sm-g986u that be carrier version

Sent from my SM-S918U1 using Tapatalk

 

[mustang7757]

If you go settings>connection>WiFi calling do u see it listed like my screen shot?

Sent from my SM-S918U1 using Tapatalk

 

[mustang7757]

So in conclusion this was a Verizon Carrier phone and someone put the Samsung unlock version on it which is fine but false advertising by eBay person

Sent from my SM-S918U1 using AC Forums mobile app

 

[swchance]

Wi-fi calling does not show up there. The sim that is in the phone is from Verizon. If I were to update the os who's would I use? Samsung or Verizon? Would doing this change the unlocked status?

 

[mustang7757]

Wi-fi calling does not show up there. The sim that is in the phone is from Verizon. If I were to update the os who's would I use? Samsung or Verizon? Would doing this change the unlocked status?

This my unlock Samsung version
ATT/Att/ATT/XAA

The XAA means =unlocked version
ATT=means ATT sim or esim installed




Sent from my SM-S918U1 using AC Forums mobile app

 

[Laura Knotek]

This is unlocked with Verizon SIM.

Sent from my SM-S908U1 using Tapatalk

 

[bigearmouse]

I bought an unlocked S21 from ebay and it does not have wifi calling. it has U1 firmware CSC code is TMB/TMB, TMB/VZW. I really want wifi calling due to spoty connection. Following the instruction from

, I change CSC to XAA, the volte calling option shows up but wifi calling options shows up for a second and disappear. I have another phone with CSC XAR which does have wifi callling option. So I change the CSC to XAR and reboot, the wifi calling finally shows up. hope that this will help others with similar issue. many of the unlocked smartphone from ebay share similar problem. They were flashed with U1 firmware but the existing CSC might not support some features that your carrier offer. YOu need to do some research and find the right CSC code to use. If your firmware version ends with U, then it's carrier specific and you might need to flash the whole new firmware in order to change CSC.

 

[mustang7757]

I bought an unlocked S21 from ebay and it does not have wifi calling. it has U1 firmware CSC code is TMB/TMB, TMB/VZW. I really want wifi calling due to spoty connection. Following the instruction from

, I change CSC to XAA, the volte calling option shows up but wifi calling options shows up for a second and disappear. I have another phone with CSC XAR which does have wifi callling option. So I change the CSC to XAR and reboot, the wifi calling finally shows up. hope that this will help others with similar issue. many of the unlocked smartphone from ebay share similar problem. They were flashed with U1 firmware but the existing CSC might not support some features that your carrier offer. YOu need to do some research and find the right CSC code to use. If your firmware version ends with U, then it's carrier specific and you might need to flash the whole new firmware in order to change CSC.

Welcome to AC!
Your device was originally a carrier version from Verizon and flashed to unlock firmware with T-Mobile sim, a lot of eBay sellers do flash the carrier version to unlock version which nothing wrong as all US version carrier or unlock are interchangeable .

 

[Rockyhud1]

Hello to Android Central,
I'm a new member here, as a result of looking for reason(s) / cause(s) for my wife's Samsung S20+ 5G phone not showing the Wi-Fi Calling feature within the Connections settings page even though my phone does display this feature and has on pretty much all networks when provisioned by the carriers - we've always had both phones registered on the same carrier/network as the same time. We've had both our phones (identical brands and models) activated with physical SIMs most recently by US Mobile (USM) on their "Warp" network (their name for Verizon), after having been a recent subscriber on Mint Mobile (on T-Mobile network) in June 2025 and before that with Good2Go Mobile on AT&T. The odd thing is her phone DID show Wi-Fi Calling while registered on Mint and earlier on Good2Go, although as I recall, that "disappeared" toward the end of our time with Good2Go about May 2025. So, I've been researching for causes and solutions for this problem with my wife's phone and found this thread in that search for info.

Most recently I got an email from a US Mobile Quality Assurance team lead, who told me the following (verbatim) after I had an unproductive chat with one of their support techs regarding this issue on my wife's phoone. "Unfortunately, there’s a known firmware issue with certain Samsung phones that prevents the Wi-Fi calling feature (toggle) from appearing in the settings. This issue stems from the manufacturer and is, regrettably, beyond our control. That said, I’d be more than happy to assist you in activating Wi-Fi calling on either our Light Speed or Dark Star network, as these networks do not face this issue. Please let us know if you’d like to teleport your line to one of these networks, and we’ll proceed right away." BTW, Light Speed is their name for T-Mobile and Dark Star is their name for AT&T - probably given those names for legal reasons.

While I appreciated the follow-up by this QA team lead, he didn't have any solutions other than transferring her phone from Verizon to either AT&T or T-Mobile, which I had explained earlier in the chat that this was NOT a viable solution as both of our phones had already been on AT&T with eSIMs provided by them and Wi-Fi Calling was never displayed on my wife's phone during that exercise and BTW, their eSIM never worked properly for connecting and registering with the AT&T network - her phone always indicated "For emergency calls only". So, long story short, when I found this thread, it gave me hope that I could hopefully resolve the issue with my wife's phone with tools and firmware from this site or other known good sites.

So, to get to the heart of things, I've pasted both my Service Provider Software Version (that does have Wi-Fi Calling feature available) and the same data from my wife's phone. I've also uploaded screenshots of these two phones' data from the respective phone's Software Information page.

My phone Service Provider Software Version:
SAOMC_SM-G986U1_OYM_VZW_13_0013
VZW/VZW,XAR/XAA

My wife's phone Service Provider Software Version:
SAOMC_SM-G986U1_OYM_XAA_13_0012
XAA/XAA,XAA/VZW

So, my question to any Android Central guru on this topic, can you examine this data and tell me how I can hopefully resolve the Wi-Fi Calling problem with my wife's phone? Any and all guidance will be very appreciated.

 

[mustang7757]

Hello to Android Central,
I'm a new member here, as a result of looking for reason(s) / cause(s) for my wife's Samsung S20+ 5G phone not showing the Wi-Fi Calling feature within the Connections settings page even though my phone does display this feature and has on pretty much all networks when provisioned by the carriers - we've always had both phones registered on the same carrier/network as the same time. We've had both our phones (identical brands and models) activated with physical SIMs most recently by US Mobile (USM) on their "Warp" network (their name for Verizon), after having been a recent subscriber on Mint Mobile (on T-Mobile network) in June 2025 and before that with Good2Go Mobile on AT&T. The odd thing is her phone DID show Wi-Fi Calling while registered on Mint and earlier on Good2Go, although as I recall, that "disappeared" toward the end of our time with Good2Go about May 2025. So, I've been researching for causes and solutions for this problem with my wife's phone and found this thread in that search for info.

Most recently I got an email from a US Mobile Quality Assurance team lead, who told me the following (verbatim) after I had an unproductive chat with one of their support techs regarding this issue on my wife's phoone. "Unfortunately, there’s a known firmware issue with certain Samsung phones that prevents the Wi-Fi calling feature (toggle) from appearing in the settings. This issue stems from the manufacturer and is, regrettably, beyond our control. That said, I’d be more than happy to assist you in activating Wi-Fi calling on either our Light Speed or Dark Star network, as these networks do not face this issue. Please let us know if you’d like to teleport your line to one of these networks, and we’ll proceed right away." BTW, Light Speed is their name for T-Mobile and Dark Star is their name for AT&T - probably given those names for legal reasons.

While I appreciated the follow-up by this QA team lead, he didn't have any solutions other than transferring her phone from Verizon to either AT&T or T-Mobile, which I had explained earlier in the chat that this was NOT a viable solution as both of our phones had already been on AT&T with eSIMs provided by them and Wi-Fi Calling was never displayed on my wife's phone during that exercise and BTW, their eSIM never worked properly for connecting and registering with the AT&T network - her phone always indicated "For emergency calls only". So, long story short, when I found this thread, it gave me hope that I could hopefully resolve the issue with my wife's phone with tools and firmware from this site or other known good sites.

So, to get to the heart of things, I've pasted both my Service Provider Software Version (that does have Wi-Fi Calling feature available) and the same data from my wife's phone. I've also uploaded screenshots of these two phones' data from the respective phone's Software Information page.

My phone Service Provider Software Version:
SAOMC_SM-G986U1_OYM_VZW_13_0013
VZW/VZW,XAR/XAA

My wife's phone Service Provider Software Version:
SAOMC_SM-G986U1_OYM_XAA_13_0012
XAA/XAA,XAA/VZW

So, my question to any Android Central guru on this topic, can you examine this data and tell me how I can hopefully resolve the Wi-Fi Calling problem with my wife's phone? Any and all guidance will be very appreciated.

Your Samsung is a factory unlocked orgin and your wife device is Verizon version with unlock firmware installed, she might need to go back to the Carrier firmware to see if it will get the WiFi calling by flashing with Odin and Frija tools on your PC

 

[Rockyhud1]

Thank you for your reply mustang7757. I've taken the info that you provided and found the Frija tool and Odin. While doing that, I discovered I had downloaded Odin (Odin3-v3.14.4.zip) some time earlier, which appears to be the latest version and I download Frija (Frija_v2.0.23364.3.zip). From what I've read, Frija currently appears to be the best tool as is seems SamFirm has been depricated or not kept up to date and maybe not as usable/compatible any more, so I'll try Frija (and Odin?) first. I found what appear to be a good set of instructions for using Frija here (https://technastic.com/frija-samsung-firmware-download-tool/) that I'll reference, likely several times, to hopefully ensure I get the firmware flashing job done without problems.

Speaking of flashing, I have a question maybe you or someone else can answer, and that is, can I change the CSC code on my wife's phone to be the same as on my phone, without causing problems with her phone as a result. In other words, with Frija, can I change the CSC code on her phone from "/VZW" to "/XAA" without creating or causing issues with her phone? (see reference data below). If so, do you have any wise suggestions or guidance that could help prevent any issues, like bricking her phone, which would be the worst outcome?

My phone Service Provider Software Version:
SAOMC_SM-G986U1_OYM_VZW_13_0013
VZW/VZW,XAR/XAA

My wife's phone Service Provider Software Version:
SAOMC_SM-G986U1_OYM_XAA_13_0012
XAA/XAA,XAA/VZW

 

[mustang7757]

Thank you for your reply mustang7757. I've taken the info that you provided and found the Frija tool and Odin. While doing that, I discovered I had downloaded Odin (Odin3-v3.14.4.zip) some time earlier, which appears to be the latest version and I download Frija (Frija_v2.0.23364.3.zip). From what I've read, Frija currently appears to be the best tool as is seems SamFirm has been depricated or not kept up to date and maybe not as usable/compatible any more, so I'll try Frija (and Odin?) first. I found what appear to be a good set of instructions for using Frija here (https://technastic.com/frija-samsung-firmware-download-tool/) that I'll reference, likely several times, to hopefully ensure I get the firmware flashing job done without problems.

Speaking of flashing, I have a question maybe you or someone else can answer, and that is, can I change the CSC code on my wife's phone to be the same as on my phone, without causing problems with her phone as a result. In other words, with Frija, can I change the CSC code on her phone from "/VZW" to "/XAA" without creating or causing issues with her phone? (see reference data below). If so, do you have any wise suggestions or guidance that could help prevent any issues, like bricking her phone, which would be the worst outcome?

My phone Service Provider Software Version:
SAOMC_SM-G986U1_OYM_VZW_13_0013
VZW/VZW,XAR/XAA

My wife's phone Service Provider Software Version:
SAOMC_SM-G986U1_OYM_XAA_13_0012
XAA/XAA,XAA/VZW

Hi
So you can't change the CSC the last 3 letters its where the device orginated , u can change the CSC when u flash Odin and use different CSC in that slot , it's a little confusing but if you want carrier features I would not suggest this because it can stop future updates and would need to flash stock CSC to receive updates again so for you don't try .

Now your wife's phone is on the same firmware as yours someone at one point flash her carrier version to the unlocked firmware.

The stock Samsung firmwares unlocked is model number that ends with U1 and the carrier version is U only at the end of the model number.

XAA is Samsung unlocked firmware CSC
Tmb is T-Mobile
Vze is Verizon

Now we are a dealing with all official Samsung firmware which means you cant brick it like say you installing a custom ROM or different recovery.

To flash between carrier and unlock firmware you would need the latest Odin Patch B and Frija firmware tool I usually download from XDA Forums website if you type a search there for those 2 things .

I would suggest she goes back on the carrier firmware if still doesn't get the results can flash back to the unlocked she has on it .

I can guide you with the process on how to do this

 

[Rockyhud1]

Thanks again for the info and offer to help, mustang7757. The one issue I'm trying resolve is my wife's Galaxy S20+ 5G currently hasn't gotten provisioned for Wi-Fi Calling, no matter what US Mobile (USM is an MVNO / reseller of network access and is our current cell phone plan provider) has done. BTW, both of our phones are using physical SIMs to access Verizon due to various issues with eSIMs issued from USM (for both phones) to access AT&T and T-Mobile before we were finally "migrated" to Verizon (at my insistence). Prior to USM, we used Mint Mobile service (running on T-Mo network) a short time before switching to USM and both phones had Wi-Fi Calling available. We would have stayed with Mint had it not been for the very weak and unreliable signal due to our physical location not being near cell towers from any carrier, although Verizon does have a couple closer than AT&T and T-Mo, which is why I decided to try USM as they have access to all 3 carriers. My phone, also a Galaxy S20+ 5G, has never been such a challenge to get Wi-Fi Calling enabled when the service provider has been notified of it not being provisioned. As for getting updates, both of our phones have received Samsung updates at roughly the same time (give or take a few days) and are currently at the same update level. So, in my mind, I was thinking if I can flash my wife's phone to be the same firmware as mine, then hopefully this would resolve the Wi-Fi Calling issue on her phone.

As it's getting later in the afternoon today, I'll get back to you on your offer to guide me with the process. I'd like to get Frija and Odin installed on my Windows PC so I can get somewhat familiar with it before I start making any firmware changes on her phone.