can't enable wifi calling on LM-G900UM

[mkevinh]

I have a velvet LM-G900UM. I would like to enable wifi calling, but the option is grayed out. Software version shows as G900UM20m.
I'm wondering if changing the firmware to one of those listed on this page will solve my problem?

LG G900UM(LMG900UM) aka LG Velvet 5G - LG-Firmwares.com

LG G900UM download the firmware for free! Detailed installation instruction. Video review of the model and its features. User feedback and latest news.

lg-firmwares.com

If so, which would I use? I'm a rookie....totally clueless.

 

[Baljeet Khairwal]

You can try European LM-G900EM Firmware using patched LG Up Tool.

 

[mkevinh]

i noticed that under the link that i provided above, there are firmware versions that say "Open" in the description....does anyone know if that indicates lack of AT&T locks in the software?

 

[mkevinh]

when i try to run lg up, i get a failure message. i tried using uppercut, and i see the phone connected, select the firmware file, and when I start, it shows progress going to 4% and then the software crashes (windows). I have read other threads indicating a similar problem. i was trying to change the firmware to G900UM20j_00_OPEN_CA_OP_1027.kdz
do i need to do something else prior to using lg up, maybe unlock bootloader? i've turn on unlock and usb debug in system options, and also turned off usb debug....no difference.

i have not tried flashing to the european firmware...i wanted to try the canadian version that has "OPEN" in the name, hoping that it might not have the at&t controls/locks.