1) Replace the NIMU ethernet driver file "nimu_eth.c" in PDK's NIMU package location.

Ex:
C:\ti\pdk_C6678_1_1_2_6\packages\ti\transport\ndk\nimu\src

2) Replace the platform file and PHY driver in PDK's platform directory.

Ex:
C:\ti\pdk_C6678_1_1_2_6\packages\ti\platform\evmc6678l\platform_lib\src

3) Import the NIMU driver and platform package into CCS and rebuild.

Ex:
Import the following packages with mentioning the following location.

C:\ti\pdk_C6678_1_1_2_6\packages\ti\platform\evmc6678l\platform_lib
C:\ti\pdk_C6678_1_1_2_6\packages\ti\transport\ndk\nimu

4) Link and use the rebuilt new NIMU and plaform package with your NDK example for EMAC0 support on AMC connector.