I've just flashed Ubuntu on my Nexus 5 using magic-device-tool. (I've used desktop Ubuntu for years, but this is my first time using it on a mobile device.) Everything seems to be working fine on wifi, but when I switch wifi off, I can't get an internet connection. My network connections show Cellular Data is enabled, with "Sprint 4G" appearing under that setting (that text is gray; not sure if that means anything), and bars are full.
I've had problems with Sprint data on this phone when using Cyanogenmod (there's a thread on the subject at XDA Developers); not sure if that's relevant or if this is a different problem.
I tried poking around under "Cellular Settings" but haven't had any luck; setting either "Automatic" or "Sprint" under "Carrier" doesn't seem to work, and I don't know what to set under APN (if anything).
Appreciate any ideas; thanks.
EDIT TO ADD: It turns out it wasn't just data; phone calls didn't work either. I tried calling my wife's phone; I heard one ring on my phone and then nothing, and her phone never rang.
Since this is my primary phone, I switched back to Android (LineageOS) for now, but I'd like to try Ubuntu again in the future if anyone has any suggestions. (Maybe I'll wait for 16.04.)