On both of my packet squirrel units, I found that after the upgrade to 3.0 they would not connect to the C2 server;
I found this:
root@squirrel:/etc/init.d# ls -lah
drwxr-xr-x 1 root root 0 Aug 5 21:29 .
drwxr-xr-x 1 root root 0 Aug 13 12:25 ..
----SNIP----
-rw-r--r-- 1 root root 361 Aug 5 21:28 cc-client
----SNIP----
root@squirrel:/etc/init.d#
Once I chmod that to make it executable (chmod 755 chmod 755 /etc/init.d/cc-client) - my devices connect to C2 properly once more.
I hope this helps other users with the same issue as me, and helps the devs fix the current image.