Fix MAC Address

Ethernet devices are typically assigned a unique MAC address that they should use for life.

It is important that the MAC address is kept associated with the device, and is kept somewhere safe.

To achieve this, the 4Kopen boards store their MAC address as a U-Boot environment file at an offset of {{0xd0000}} in the SPI flash.

If you need to restore or alter your MAC address, the following pages will help you do this from either U-Boot, or Linux.