Hi,
I've encountered the same issues with the Fibocom L860Gl it seems that these modem modules are made specifically for certain Lenovo and HP laptop models. But luckily after doing a lot of research I ended up with only one solution to get them connecting to the internet. I see that you've installed all the right firmware using intel flash tool so what you need to do next is use dial up to connect to the internet. check out this tutorial video and just follow the steps.
https://www.youtube.com/watch?v=sAqJXSerjJM&t=15s
and if you not sure if you installed the firmware correctly here's the tutorial I used.
https://radenku.com/upgrade-firmware-fibocom-l850-gl-l860-gl/