Same problem here.
Data transfer via USB was fine. But after I updated to build fp2-sibon-18.02.0
the phone did not react to an USB connection to my desktop at all. There were no logs on the desktop, either (Debian linux buster/testing). USB charger worked as expected, though.
This is with the same cable, same USB receptacle on the same desktop as before. Changing any of these usual suspects did not affect the problem at all.
What did work, was the a similar fix as presented by SebG above. That is:
- activate developer mode (by tapping the build number several times in the about phone screen)
- activate ‘USB debugging’ in the developer options
With this in place, my FP2 reacts as expected when it is connected to my desktop via USB. I immediately get a response and can choose the USB mode from the notification tab. This still works after a reboot and even if I disable developer mode.
( Settings → Apps → Settings → Storage → Clear_Data )
So it looks like USB connection to a desktop requires ‘USB debugging’ activated. With hindsight, it may have been me fiddling with developer mode options rather than the update. Not being able to connect properly to a desktop without ‘USB debugging’ enabled is a little surprising, though.