@vantage:
(1) Open file rbfeeder.ini
sudo nano /etc/rbfeeder.ini
(2) Scroll down till you see following:
[dump978]
dump978_enabled=true
Change true to false so it becomes:
[dump978]
dump978_enabled=false
(3) Save file (Ctrl+O) and close (Ctrl+x)
(4) Restart rbfeeder
sudo systemctl restart rbfeeder
(5) Above is enough to stop irritating warning "Can't connect to 978 source".
However if you are not running dump978-rb, better to disable it, otherwise it unnecessarily keeps running in background, genersting its own log "unable to find the dongle". To stop it do following:
sudo systemctl stop dump978-rb
sudo systemctl disable dump978-rb
(6) If anytime you get a second dongle for 978, you can enable and start dump978-rb by following commands:
sudo systemctl enable dump978-rb
sudo systemctl start dump978-rb