I have been attempting to build Lineage 15.1 for samsung S6 edge (zeroltexx) and S6 (zerofltexx) for a couple of weeks on and off now and I am getting the same issues every time. I have two phones - a S6 and a S6 Edge. The S6 Edge has a cracked screen so this is the one I am testing with. The S6 is my daily phone so this is still running Official Lineage 14.1 downloaded from the official sources.
I have a couple of spare Dell PC's - an i7 machine with 24GB RAM and 2 * 1TB disks and a Core2 Quad with 16GB RAM and 2 * 640GB disks. I have wiped and installed Ubuntu 18.04, followed the procedure to the letter for configuring the environment, installing the prerequisites and downloading the repositories. This is the guide I have followed - https://wiki.lineageos.org/devices/zeroltexx/build
I changed the repo init command to download lineage-15.1 rather than cm-14.1 and I have added the zero.xml from here - https://github.com/Exynos7420/local_manifests
to the /.repo/local_manifests/ folder. Everything seems to sync OK when I do a repo sync. The samsung bits get added to the /device/, /vendor/, /hardware/ & /kernel folders. The ROM seems to build OK, I transfer it to the zeroltexx, boot to TWRP, perform a full wipe and then install the ROM and OpenGApps. When the device boots there is no RIL (mobile network or data), no audio and no GPS. WiFi works, Bluetooth works, NFC works, screen works, vibration works, camera works, fingerprint sensor works and its a fairly smooth UI.
I have wiped and rebuilt the Ubuntu system and rebuilt the environment so many times I can't remember. I have also tried building within Windows 10 Insider Preview with WSL enabled using the guide on XDA. I have even just tried it within ESXi 6.0 and using Ubuntu 16.04, however the resulting ROMs all suffer from the same issue with RIL, Audio and GPS not working.
I am obviously missing something and its the same thing each time.
Any idea what I am doing wrong?