SW4STM32 and SW4Linux fully supports the STM32MP1 asymmetric multicore Cortex/A7+M4 MPUs

   With System Workbench for Linux, Embedded Linux on the STM32MP1 family of MPUs from ST was never as simple to build and maintain, even for newcomers in the Linux world. And, if you install System Workbench for Linux in System Workbench for STM32 you can seamlessly develop and debug asymmetric applications running partly on Linux, partly on the Cortex-M4.
You can get more information from the ac6-tools website and download (registration required) various documents highlighting:

System Workbench for STM32

You are viewing a reply to lwIP on Nucleo-F767ZI  

I just look at your post; if you read the Nucleo-F767ZI user manual, available at ((http://www.st.com/content/ccc/resource/technical/document/user_manual/group0/26/49/90/2e/33/0d/4a/da/DM00244518/files/DM00244518.pdf/jcr:content/translations/en.DM00244518.pdf)) you’ll see that the Ethernet PHY is connected to the STM32 using an RMII interface, not an MII interface as you say you have configured under CubeMX.

You shoud then modify your CubeMX configuration, by running again CubeMX using the same .ioc file, then regenerate the code (save your old custom code just in case) and it should work better...

Bernard (Ac6)