This will occur if your board's MAC address has been erased from flash memory. The Nios II factory-safe design allows you to re-configure the board with a unique MAC address based on the serial number of the development board. This must be done before the factory-safe web server example design will operate. To set the board's MAC address, connect to the board with a JTAG download cable (ByteBlaster, etc.), and perform the following steps:
1. Open the Nios II SDK shell from the Nios II folder of your start menu.
2. Open a second Nios II SDK shell
3. Reset the development board to load the factory-safe design by pressing the "Force Safe" button.
4. In the first SDK shell window, reset the Nios II processor by typing: "nios2-download --reset-target"
5. In the second SDK shell window, type "nios2-terminal" to start STDIO communication with the JTAG UART on the factory-safe design.
6. In the first SDK shell window, direct the CPU to begin execution of the design by typing: "nios2-download --go"
7. In the second SDK shell window, you should see a prompt to enter the serial number from your Nios development board. This is the 9-digit numeric string that begins with "ASJ" on a sticker on the development board. Enter this number and press return. The factory-safe design will generate a new MAC address and write it to flash.