We have a custom designed board based on i.mx6q sabresd board. The Ethernet PHY is changed from AR8031 to AR8035. When we start to bring up the board based on Linux 3.0.35 and 3.0.101, the ethernet could run at 1Gb/Full and get dynamic IP instantly from our Wifi AP. However, when we migrate to 3.14.28, we discovered the Gigbabit could not work anymore. Unless we switch it back to 100M/Full using ethtool, it does not get any dynamic from the dhcp host. In addition, we notices that the Orange light on the does not flash at all. We also migrate the board to 4.1.15 but the same outcome occurrs. On the other hand, the same kernel could run on the Sabresd EVB without this problem. Could you give me some idea why this happens?