Arduino Due RMII (PHY?)

Apologies if I get any terminologies wrong here, but I currently have a ksz9477s ethernet switch (chosen as it can accept an SFP module) which is wired to a custom Arduino due (ATsam3x8e) via an RMII interface.

The ksZ9477s is all working and has been tested, but I can't for the life of me get the RMII interface to work on the Due, or more to the point, I can't find any example, bar the TAIJIUINO, of anyone using the RMII/MII interface on the Due (TAIJIUINO code seems to be incompatible even after converting EMAC to RMII)

Basically, does anyone know where to find the resources to program the Due with its RMII port?

The Ethernet interface is inaccessible on the standard Due board.

Tell us exactly what you have.

I custom made the board myself, i.e bought the ATsam3x8e from microchip (well RS components), and custom designed a PCB with it and the ksz9477s

I'm just calling it a Due as it uses that as the base design

Did you see this Application Note from Atmel :

Plus pages 1252 to 1253 of Sam3x datasheet ( RMII Transmit and Receive Operation)

BTW, the DUE core, an DUE compatble board, is provided with all ethernet pins broken out:

To find some ethernet example codes, you could search in other SAM uc sharing the same EMAC peripheral, e.g. SAMA5D3: