According to the documentation, the Microchip-specific fixed part of the MAC address should be 0x00, 0x04, and 0xA3. The firmware always reads 0x00, 0x1E, and 0xC0. With this fixed component, the board also works without problems, however, these do not match the documentation. Why is this?
Due to demand for these devices, we had to add additional fixed addresses to keep up with the number of shipped pre-programmed parts 2K I²C Serial EEPROMs with EUI-48 or EUI-64. Documentation is in the process of being updated. Please read more about Node Identity in the datasheet.
Currently, Microchip's OUIs are 0x0004A3, 0X001EC0, 0xD88039, and 0x5410EC, though this will change as addresses are exhausted.
For more information, please watch Microchip's EUI-48 Enabled MAC Address Chips Webinar.