I also have the sound problem. While trying to solve it, I also encounter various other error messages. Trying to fix things, I get messages in Terminal that various updates fail. This is one of them I have been trying to solve:
Errors were encountered while processing: grub-efi-amd64-signed
When I restart the Atomic Pi, it takes exactly 2 minutes and 41 seconds until I get the login screen. The screen says
Checking media presence......
Start PXE over IPv4.
Then after a while, it changes to the same, except IPv6
(I have an Ethernet cable connected to the router, because the WiFi is very weak/slow. Do I need to buy a WiFi antenna and attach it somewhere?)
I didn't insert any memory card, is that needed? The following is connected (I got the Atomipc Pi with breakout board):
USB keyboard (no hub)
USB mouse dongle (for wireless mouse) on breakout board USB port
5V 6A power supply to the breakout board green connector
Ethernet cable directly into router
I changed the sign on name and password, and I set a root password.
The sound doesn't work. If I start the test mentioned in another thread, I get white noise in left and right channel, using address 0,2. I have been where I could open the volume control, but now when I open it to settings, it says something about cannot connect, trying again in 5 seconds.
Youtube doesn't work in Chromium nor Firefox. It loads up but a circular
loading rotating arrow is all I get. If I log into Facebook, I can see videos. But a few minutes of Facebook or other feature rich websites, makes the browser and eventually the entire Ubunto crash. To an extent where even CTRL-ALT-DEL doesn't work any more.
My experience with Raspberry Pi and Unix/Linux/Ubuntu is quite limited (Normally using Max OS X)