[LG Wing Guides, News, & Discussion] Vuche:
Good news for anyone having the Wing fall Back to 3G when making a call. You can activate VoLTE using a mix of the two following guides:

https://xdaforums.com/t/guide-how-t...owifi-viwifi-lg-devices-lg-velvet-5g.4488803/

and

https://xdaforums.com/t/lg-g8x-g8-v60-volte-enable-for-all-carriers-unlisted-countries-also.4575655/

To make it as short as possible:

1) Create an empty directory named "enable_ue" in the root of the phone's main storage, using you prefered file explorer (like for exemple Cx Explorer or ).

2) From the LG Phone dialpad and with your SIM card inserted, type #*462633*#100# (for european LG Wing - LM-F100EMW) to get into the Hidden Menu. From there enter Field Test, then Universal Enabler -> Create New Config. Click on the four last check boxes VoLTE, ViLTE, VoWIFI and ViWIFI to enable these options. You won't be able to enter this setting if you haven't created the empty directory under point 1).

Go back to Field Test and enter Modem Setting to enable 5G if you haven't already -> RAT Selection -> SIM 1 Mode - > select GSM/WCDMA/LTE/5G or whatever you need + 5G. Go back and do the same with SIM 2 after, if you use it. Network mode in the network settings will then not show "5G prefered", but a number, like "26" in my case.

3) Go back to Field Test menu and enter IMS Stting. If you have Slot - 0 : OPEN / EU and Slot - 1 : OPEN / EU (or something else on each side of the / ), then you did everything right to this point. Exit the Hidden Menu and get your SIM out of the phone.

4) Enter th Hidden Menu again without the SIM inserted. Go back to IMS Setting and click on Slot - 0.

Under Subscriber enable IMS,ISIM & USIM.

Under Xcap\Ut. -> General, enable UT & USSD Over IMS

Under ETC, enable Check IMS Registration, Use rule-ID from responsem& Query on bootup

Under GPRI VoLTE/VoWIFi, enable VoLTE, ViLTE, VoWIFI & VIWIFI

Under Test, Preference Operator can be set as OPEN (what I did), or your carrier short name, or your County. Apparently does not make difference for some operator but some do require it to same name as theirs.

Preference Country this is important as this decides if VoLTE gets enabled, Find your country short code example USA is US , India is IN. Europe is EU. Find and try different short codes, I put EU.

Enable Support Volte AT command, VoNR, UAC Enabled & VoLTE Setting Enabled

You can now exit the Hidden Menu & insert your SIM back in. If everything went well, you should see the VoLTE icon showing up on the left of the network in the task bar, on the (my) Wing it's a small lifted phone headset with wave coming out of it. If you don't have it, check under the phone network settings - Mobile networks, if you got the VoLTE option and if it's activated. You might have to repeat some of the steps above with the SIM card inserted (as I had to) to make it work. Don't forget to check the settings for both SIMs if you use two. Not sure if all setting are kept if you reboot or reset the phone. You might have to repeat the preocess or part of it on each reboot, as for enabeling the 5G option.

Was tested on Android 12, as my phone didn't get Android 13 yet. But it's also working on my Velvet 5G that is on A13.

Many thanks to Baljeet Khairwal and johndaniel for their guides + all other persons who helped in the two threads.