There is the following branch ready to be tested with ubports-qa: xenial_-_add-samsung-quirks
I need testers to confirm that:

a) this patch does not change anything on Non-Samsung devices
b) this patch improves Samsung devices

You will need a SIM card for this which is able to make calls. I do not give specific instructions here for how to install qa branches, as otherwise unexperienced testers might break smth

Installation

1. Mount a tmpfs so apt can breathe:

sudo mount -t tmpfs tmpfs /var/cache/apt/archives

2. Install the repository:

sudo ubports-qa install xenial_-_add-samsung-quirks

3. Reboot your phone.

Test cases

• Enter PIN, get network operator indication and signal strength
• Have data connection
• Get an inbound call answered
• Make an outbound call
• Hang-up an inbound or outbound call

How to enable the Samsung mode?
You need to set ril.device=samsung_msm_822x in your device property file.

I hope I can get some wider results. To me it looks already working very well.