[Guide] Enable AT&T US HD Voice/VoLTE on non-supported W10M phones

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73blazer

Member
Feb 16, 2022
17
4
Just curious if anyone currently has a 950XL in the United States that is functioning with VoLTE on T-mobile or ATT after the 3g shutdown.

I'm currently using a 640 LTE RM 1073 with T-mobile Windows 8 that drops back to 4g or 2g for voice calls and maintains an LTE connection otherwise.
That's what the latter part of this thread is about at least for AT&T, can't speak for t-mobile. Read through the last couple pages on how to get a 950XL on ATT
 

nate0

Senior Member
Mar 27, 2015
965
158
Just curious if anyone currently has a 950XL in the United States that is functioning with VoLTE on T-mobile or ATT after the 3g shutdown.

I'm currently using a 640 LTE RM 1073 with T-mobile Windows 8 that drops back to 4g or 2g for voice calls and maintains an LTE connection otherwise.
I am tempted to get another 950xl, but I am on Google Fi...have been on Fi since losing my last bit of patience with T-mobile as they have THE worst customer service I have experienced with any provider in the last decade.
 

Old_Mil

Member
Aug 30, 2018
18
7
I am tempted to get another 950xl, but I am on Google Fi...have been on Fi since losing my last bit of patience with T-mobile as they have THE worst customer service I have experienced with any provider in the last decade.
I'm with Mint now, it works well. T-mobile's network without the customer service, monetization of your usage, and you're pretty well free to swap handsets, APNs, etc as you wish. Also, it's one of the few MVNOs, if not the only one, that allows international roaming (you have to buy gigs and minutes through their website) when you travel.

I was just wondering with the latest changes to cellular networks in the US and the 3G/2G drawdown what people's experiences were with regards to VoLTE, HD voice, call reliability, and (if anyone is using it) Wifi calling in the summer of 2022.
 

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    This is how I enabled AT&T US HD Voice/VoLTE on the Lumia 950 XL Dual sim and the factory Unlocked Alcatel IDOL 4s. It should work on the Lumia 950 Dual sim too, but I have not tested this method on it yet.

    *Requires full file system access with MTP or SFTP using Interop tools
    *All the files attached were taken from the latest AT&T Lumia 950 FFU (01078.00053.16236.35035 - OS 10.0.10586.318)
    *To reset everything back to original factory settings requires either a re-flash or you can take the files you backed up before hand and replace them back.
    **The one caveat to this is you need to use an AT&T Lumia 950 imei to register to your ICCID (sim card ID) with AT&T customer support to enable the hd voice/ims registration to come online. It might work with a Lumia 830 imei for AT&T too.
    ***There was mention of AT&T possibly whitelisting your device. This would allow IMS provisioning to complete without the need to have AT&T update your IMEI with that of a AT&T branded one. Seems even though you can ask AT&T to do this, it has not actually been proven to work. The only for sure way is to use a AT& branded Lumia 950 IMEI.

    Update 7/20/2017: Updated files attached to include the specific ATT-US files from the 950 XL rom RM-1085_15919 (product: 059X7S5). The modem file is slightly different as it provisions with the same bands that come default already on the 950XL, it will not remove band 17 like the 950 ATT modemconfiguration.cab file does. The modem files as far as I know only work on the x50 Lumia models and not OEM models.

    Install Interop Tools
    - Here is the link. I used version InteropTools_1.9.437.0_arm_RC3.

    Install Swish
    - This sftp client found here (needed for Lumia 950/XL) for explorer sftp support. For the IDOL 4s enable Full file system access via MTP with read write access in Interop Tools under the Unlock options/settings.

    Gain access to the file systems using Interop Tools app.
    - In Interop Tools go the SSH--Account Manager and add an account. The account user name should be System.

    - Tap the account System so it is highlighted and then tap templates to use.

    - Tap enable full file system access with sftp. Then go to the template options and hit the authentication drop down setting it to password.

    - Add the password (4 digit pin of your choice).

    - Once your phone is on wifi, add an SFTP Connection under Swish. Set the user to system. Set the path to /c/. Once added double click it and login with the pin you set. Explorer will open with your phones files. There is a guide in more detail on sftp file system access made by snickler if you need to see more details about this method.


    For the Lumia 950/XL do the below:
    - Copy and back up all files under C:\Programs\CommonFiles\ADC\Microsoft and C:\Programs\CommonFiles\ADC\OEM.

    - Then Copy and replace the files under C:\Programs\CommonFiles\ADC\Microsoft and C:\Programs\CommonFiles\ADC\OEM with the files of the zip file titled ADC.zip

    - Copy and backup the file under C:\Programs\CommonFiles\OEM\Public\MMO\Multivariant.

    - Then Copy and replace the file under C:\Programs\CommonFiles\OEM\Public\MMO\Multivariant with the contents of the zip file titled modemconfiguration.zip

    - From there do a hard reset.


    For the Alcatel IDOL 4s do the below using full file system access with MTP:
    - Copy and backup all the files under C:\Programs\CommonFiles\ADC\Microsoft and C:\Programs\CommonFiles\ADC\OEM.

    - Then Copy and replace the files under C:\Programs\CommonFiles\ADC\Microsoft and C:\Programs\CommonFiles\ADC\OEM with the contents of the zip file titled ADC.zip

    - From there do a hard reset.


    When the OOBE setup returns after hard reset, you may have a light blue/cyan theme and the display/dpi/font size may be a bit different too. This is due to the packages used from the AT&T 950. Go through the normal setup and let it fully boot to the start screen. Wait for the prompt to tell you to reboot your phone for settings/sim card settings to change/update.

    Alternatively you can add the two files in the zip file titled MO_VoLTE_1117.zip to the c:\windows\system32. This will replace the MO_VoLTE_Label_1117.dll and MO_VoLTE_Description_1117.dll details found near the volte toggle under Sim settings with the proper descriptions.

    To reset everything back to original factory settings requires either a re-flash or you can take the files you backed up prior and replace them back.

    Thanks to the creator of interop tools @gus33000. Without access to that tool/app this and other things like this would not be possible. To @snickler for finding and explaining the sftp file system access in a guide to help others like me use that method.
    1
    This is how I enabled AT&T US HD Voice/VoLTE on the Lumia 950 XL Dual sim and the factory Unlocked Alcatel IDOL 4s. It should work on the Lumia 950 Dual sim too, but I have not tested this method on it yet.

    *Requires full file system access with MTP or SFTP using Interop tools
    *All the files attached were taken from the latest AT&T Lumia 950 FFU (01078.00053.16236.35035 - OS 10.0.10586.318)
    *To reset everything back to original factory settings requires either a re-flash or you can take the files you backed up before hand and replace them back.
    **The one caveat to this is you need to use an AT&T Lumia 950 imei to register to your ICCID (sim card ID) with AT&T customer support to enable the hd voice/ims registration to come online. It may work with lets say a Lumia 830 imei for AT&T too. I do not have one anymore to test though.

    Update 7/20/2017: Updated files attached to include the specific ATT-US files from the 950 XL rom RM-1085_15919 (product: 059X7S5). The modem file is slightly different as it provisions with the same bands that come default already on the 950XL, it will not remove band 17 like the 950 ATT modemconfiguration.cab file does. The modem files as far as I know only work on the x50 Lumia models and not OEM models.

    Install Interop Tools
    - Here is the link. I used version InteropTools_1.9.437.0_arm_RC3.

    Install Swish
    - This sftp client found here (needed for Lumia 950/XL) for explorer sftp support. For the IDOL 4s enable Full file system access via MTP with read write access in Interop Tools under the Unlock options/settings.

    Gain access to the file systems using Interop Tools app.
    - In Interop Tools go the SSH--Account Manager and add an account. The account user name should be System.

    - Tap the account System so it is highlighted and then tap templates to use.

    - Tap enable full file system access with sftp. Then go to the template options and hit the authentication drop down setting it to password.

    - Add the password (4 digit pin of your choice).

    - Once your phone is on wifi, add an SFTP Connection under Swish. Set the user to system. Set the path to /c/. Once added double click it and login with the pin you set. Explorer will open with your phones files. There is a guide in more detail on sftp file system access made by snickler if you need to see more details about this method.


    For the Lumia 950/XL do the below:
    - Copy and back up all files under C:\Programs\CommonFiles\ADC\Microsoft and C:\Programs\CommonFiles\ADC\OEM.

    - Then Copy and replace the files under C:\Programs\CommonFiles\ADC\Microsoft and C:\Programs\CommonFiles\ADC\OEM with the files of the zip file titled ADC.zip

    - Copy and backup the file under C:\Programs\CommonFiles\OEM\Public\MMO\Multivariant.

    - Then Copy and replace the file under C:\Programs\CommonFiles\OEM\Public\MMO\Multivariant with the contents of the zip file titled modemconfiguration.zip

    - From there do a hard reset.


    For the Alcatel IDOL 4s do the below using full file system access with MTP:
    - Copy and backup all the files under C:\Programs\CommonFiles\ADC\Microsoft and C:\Programs\CommonFiles\ADC\OEM.

    - Then Copy and replace the files under C:\Programs\CommonFiles\ADC\Microsoft and C:\Programs\CommonFiles\ADC\OEM with the contents of the zip file titled ADC.zip

    - From there do a hard reset.


    When the OOBE setup returns after hard reset, you may have a light blue/cyan theme and the display/dpi/font size may be a bit different too. This is due to the packages used from the AT&T 950. Go through the normal setup and let it fully boot to the start screen. Wait for the prompt to tell you to reboot your phone for settings/sim card settings to change/update.

    Alternatively you can add the two files in the zip file titled MO_VoLTE_1117.zip to the c:\windows\system32. This will replace the MO_VoLTE_Label_1117.dll and MO_VoLTE_Description_1117.dll details found near the volte toggle under Sim settings with the proper descriptions.

    To reset everything back to original factory settings requires either a re-flash or you can take the files you backed up prior and replace them back.

    Thanks to the creator of interop tools @gus33000. Without access to that tool/app this and other things like this would not be possible. To @snickler for finding and explaining the sftp file system access in a guide to help others like me use that method.
    It worked on my Lumia 950 XL
    Look on LumiaFirmware.com for an FFU from your provider (in my case the Lumia 950) mount it with ImgMount and extract the files mentioned above.
    for me no reset was necessary, as soon as I pasted the files in the ADC folder I got a message that "SIM settings have been changed please restart" and IMS registration was on
    That's my findings so far
    1
    I want to enable it for "Jio" a carrier in INDIA that provides VoLTE services but only android and ios users are able to use it and they donot sell a specific lumia with VoLTE services or there carrier name on it.
    *I am using L950XL DS Indian Variant.
    *Is this possible??? If yes can you guide me how to edit configuration files to do this.
    I was mainly referring to US carriers. You would need to get a hold of a Windows 10 Mobile handset that supports VoLTE on Jio and build new nvi file entries for the Lumia. I don't know of a model that would support Jio VoLTE except maybe the IDOL 4s Pro model that support European Countries. Once you find a Windows 10 Mobile phone that supports VoLTE on that carrier you a starting point.
    1
    @spe317
    Since you are reflashing anyway...once you verify all the files are in place. Do full_nvi_update not factory_reset.

    thor2.exe -mode uefiflash -ffufile <ffufile_RM-xxxx.ffu> -do_full_nvi_update -skip_flash -reboot

    This leaves the modem alone as a single sim, and only reintializes the NVI settings with an update from the nvi files.
    If still having an issue you can try a hard reset too. I am not certain why your sim would be doing this...Are you using the Lumia 950 modemconfiguraton.cab file from my first post or are you using the 950 XL files I attached (File Type: zip 950XL_RM-1085_15919_ATT-US_files.zip)
    1
    I had that happen once to an AT&T sim. Except it was not as obvious as yours...my issue was that it would just not lock LTE bands. Took me a week to realize it was due to a bad sim. Glad you caught it quick.

    Just confirmed with ATT and received an IMS lock. Provisioned my phone unbranded 950xl DS. Thanks!