In latest i.MX6UL/i.MX6ULL EVK boards, Ethernet PHY chip is upgraded with new revsion ID (01) although the same part number KSZ8081RNBIA is used. The detailed change is as follows:
Mark on old Ethernet PHY chip (Silicon Revision ID is 0, Mark is A2):
Mark on new Ethernet PHY chip (Silicon Revision ID is 1, Mark is A3)
Linux BSP requires to be updated to support this new Ethernet PHY because PHY setting is designed to be associated with silicon ID. See attached patch for the details (Please note: i.MX6ULL/i.MX6UL EVK shared the same board file.)
The formal patch is also included into the releases starting from L4.1.15_2.0.1. See http://git.freescale.com/git/cgit.cgi/imx/meta-fsl-bsp-release.git/tree/imx/meta-bsp/recipes-kernel/linux/files?id=imx_4.1.15_2.0.1
If ethernet doesn't function on your i.MX6UL/i.MX6ULL EVK board in kernel, please check whether Silicon Revion Mark is A3 on the board and then apply for attached file for the test.