I am using the Adafruit Ethernet FeatherWing board using your W5500 chip. The board is connected to my network via a NetGear Gigabit Hub. I am having issues with the auto-negotiation not working correctly all the time. It sometimes negotiates at 100Mb but most of the time it negotiates at 10Mb. I am using the LED’s on the Hub for the speed negotiated with the hub.