The Netzer EEPROM is erased (set to 0xff) with this project. Not erased is the MAC address which also resides in EEPROM.
The project is uploaded via TFTP like described here.
During the project is running the Netzer is not accessible from network.
After the EEPROM is erased it signals successful erase with fast blinking network LEDs.
Now you should make a reset and upload another project.
The new project detects the empty EEPROM and automatically executes reset to factory settings.