In some cases you want to use the Ethernet port of the Ground SBC to connect to a laptop for instance. In this case you can enable the Ethernet Hotspot.
Enable the Ethernet hotspot
Disable the Ethernet hotspot
Don't use a switch or Hub, directly connect the RJ-45 cable. The Pi will be IP 192.168.1.1 the connected PC will be 192.168.1.2. Using a Switch or Hub won't work since the current implementation only supports one connected device.
When the Ethernet hotspot is on, the WiFi hotspot doesn't work.
If you are trying to ssh into the groundpi, turn OFF the Ethernet hotspot setting. If ethernet is connected to a router then get the pi IP address from the router.