Which interface gets connected to which EUSART?

Deciding how to configure the EUSARTs based on which interface devices are available
AvailableConnect / Driver
WiFiUSR IoTSWNEUSART1EUSART2
NoNoNoSWN / SNIUSR IoT / ENI
NoNoYesSWN / SNIUSR IoT / ENI
NoYesNoSWN / SNIUSR IoT / ENI
NoYesYesSWN / SNIUSR IoT / ENI
YesNoNoSWN / SNIWiFi / ENI
YesNoYesSWN / SNIWiFi / ENI
YesYesNoUSR IoT / FD1WiFi / ENI
YesYesYesSWN / SNIWiFi / ENI
The Single Wire Network (SWN) can become available after configuring is complete if another master device supplies
the power to it. Therefore it is connected in all cases except when both Ethernet interfaces are available and it is not.

WiFi is connected to EUSART2 if available, otherwise USR IoT.