Native Ethernet LibraryWith the release of Teensy 4.1 underway I went ahead and made a library to convert existing projects using a Wiznet W5500 along with Ethernet.h to be able to make use of it's Native Ethernet. As long as your sketch doesn't make direct calls to w5100.h it will work right out of the box with no existing API changes at this time.
To make use of the native ethernet you will have to download my fork of the FNET TCP/IP stack available at: https://github.com/vjmuzik/FNET
You will also need the wrapper library to go along with it: https://github.com/vjmuzik/NativeEthernet
This wrapper library does not currently support my USB Ethernet driver, that may change in the future.
It's as simple as changing <Ethernet.h> to <NativeEthernet.h>
If you have any questions or encounter any issues please post them here so they can be addressed or fixed.