[LG G6 Guides, News, & Discussion] mrbeem:
After over a week of trying, I've come up with a solution to enable WiFi Calling (probably also VoLTE) in Fulmics ROM for LG G6 and probably G5 running any stock based ROM.

THIS GUIDE WILL ONLY WORK IF YOUR DEVICE IS ON THE LIST OF YOUR CARRIER'S VOWIFI/VOLTE SUPPORTED DEVICES AND THE SERVICE IS ENABLED THROUGH AN OTA UPDATE FOR YOUR STOCK, BRANDED ROM PROVIDED BY YOUR CARRIER!

I don't believe in magic, you shouldn't either so don't think this guide will make VoWiFi/VoLTE work on your device regardless of your carrier's support for your phone model.

Also, if your provider offers VoLTE/VoWiFi through an external app available in Play Store, don't bother reading any further.

General idea described in this guide is to tweak your rom in a way that it is recognized by your carrier as their own VoLTE/VoWiFi enabled build that has a "green light" for IMS and Xcap apns registration in your provider's VoLTE/VoWiFi service. During my attempts you make the service work on my G6 running V10t based Fulmics ROM i discovered that adding IMS and Xcap apns plus getting all the IMS and GPRI VoLTE/WoWiFi hidden menu settings right is not enough. I had everything set up right and still couldn't make a WiFi call. Then it occured to me that maybe i can't make it work because Fulmics ROM is based v10t, and my provider's VoLTE/WoWiFi enabled rom is the v10h? So i tweaked Fulmics 1.6, then 2.0 so it masks itself in front of my provider as v10h while in fact it still is v10t Fulmics ROM 2.0. And guess what... IT WORKED!!! My Carrier's IMS and Xcap apns, manually added by me to the default open-eu apn list storred in /system/etc/apns-conf.xml, got registered in the service activating WiFi Calling on my device.

How to do it step-by-step guide below :)

1. PREREQUISITES:

- /OP/[YOUR CARRIER'S CUST FOLDER IN XXX_XX NAME FORMAT] in your main dir /root. If you only have OPEN_EU in your /OP you must get your carrier's specific cust folder or install Fulmics over your carrier's VoLTE/VoWiFi enabled rom then the cust folder you need will appear in /OP

- build.prop file from your Carrier's VoLTE/VoWiFi enabled rom for your LG model (make sure following line is in the file: ro.lge.cupp_capss.rootdir=/OP

- /OP dicectory in your device main root directory with your carrier's VoLTE/VoWiFi enabled ROM's subfolder (XXX_XX format). OPEN-EU or

GLOBAL-COM are not the ones :).

- files from your carrier's rom: /root/data/ipsec/wo_apn.conf, /root/data/ipsec/wo/apn_xcap.conf

(You can try without those 2 files if you can't get them).

2. TO DO:

!!! AT SOME POINT OF CHANGING STUFF LISTED BELOW YOU WILL GET ALOT OF FC OF VARIOUS APPS. DON'T PANIC, JIST REBOOT YOUR DEVICE AND CARRY ON WITH CHANGES !!!

- in /OP directory delete folder _COMMON if you have one

- in /OP directory create a new directory called SUPERSET and set perms to 755

- copy all content from your carrier specific folder in /OP to SUPERSET. You can also just try renaming cour carrier's folder to SUPERSET instead of creating new filder and copying stuff to it.

- edit cust_group_mapping.cfg in /OP and change whatever you have after = to GLOBAL-COM

- open cust_path_mapping.cfg in /OP and make sure you have 999999,99=/OP/SUPERSET there on the list of providers

-edit official_op_resize.cfg and add SUPERSET_SIZE=[copy size value of your carrier's folder which should also be listed in the file]

-in /OP/SUPERSET (with your carrier's files coppied) edit cust.prop and in second line in the file change whatever you have after = to SUPERSET

- edit your rom current build.prop file and copy all additional stuff (in my case it was all the Fulmics ROM part of build.prop so from #Software Version down) to the build.prop acquired from your carrier's VoLTE/VoWiFi enabled rom. Add the coppied stuff at the bottom of the list.

- add following lines at the end of stuff coppied to your carrier's build.prop from step above:

persist.sys.cust.lte_config=true

persist.lg.data.iwlan.enable=true

# Debug Options

persist.dbg.ims_volte_enable=1

persist.dbg.volte_avail_ovr=1

persist.dbg.vt_avail_ovr=1

persist.dbg.wfc_avail_ovr=1

# Radio Options

persist.radio.rat_on=combine

persist.radio.data_ltd_sys_ind=1

persist.radio.data_con_rprt=1

persist.radio.calls.on.ims=1

# applying GPRI auto-commit

ro.lge.radio_gpri=1

ro.lge.amrwb_gpri=1

wlan.lge.softap5g=false

# 2015-10-12 protocol-iwlan@lge.com LGP_DATA_IWLAN [START]

persist.lg.data.iwlan=1

persist.lg.data.iwlan.ipsec.ap=1

# 2015-10-12 protocol-iwlan@lge.com LGP_DATA_IWLAN [END]

Save the build.prop file and place it over your current system default build.prop. set perms to 644

- open your device's hidden menu, go to

Field Test->GPRI VoLTE/VoWiFi->UX and tick 3rd, 4th, 5th, 6th and 9th for WoWiFi only, all except 8th for VoLTE/VoWiFi and 1st and 2nd for VoLTE only.

- go to your apns in network settings and make sure you have all the apns needed (in my case the are: internet, mms, ims and xcap). If you don't have them, try sending settings request message to your carrier's apn service center, if that doesn't help, add the apns manually (you must find your carrier's specific manual settings on the internet). You can also edit /system/etc/apns-conf.xml file and add missing apns manually to the list in above file. To do that you must find your carrier's apns on the list first, (list order by MCC-MNC code) under your carrier's last apn enter your VoLTE/VoWiFi apns in the same way the other apns in the file are typed.

-save apns-conf.xml, go back to apn list in network settings, tap overview->restore defaults and the missing apns you added to your xml file should appear on the list in network settings.

-make sure you have all permissions right of the created/coppied/edited files and reboot your device.

When your phone boots back up to Fulmics you should have your carrier's boot animation instead of default LG one, then you should see initial boot screen with "android is setting up" for a couple of seconds, then your homescreen. When configuring of your sustem is done, open quick settings and your VoLTE and WiFi Calling tiles should appear there. Turn on what you want and test if it's working. Remember, with VoWiFi you must have both WiFi and WiFi calling ON. The easiest way to tell if WiFi Calling is active is the presence of a headphone with little WiFi icon on the status bar and other places in your dialer etc. To test, turn on airplane mode, wait till WiFi gets turned off, turn it back on in airplane mode, wait for WiFi calling icon on status bar and try to make a call with airplane mode on :).

REMEMBER! This guide will will only work if your carrier verifies WiFi enabled devices by 3 conditions: 1. Device supported, 2. Apns present, 3. ROM build match (info from build.prop).

I might have forgotten about something (or not:) ) but will edit if or when questions start to be asked :)

A picture of WiFi Calling working on my device with Fulmics rom 2.0 below. (WiFi Calling icon next to WiFi icon in status bar.