28.8.1.1 Prerequisites

The device's fuses must be configured to reserve a sufficient number of FLASH memory rows for use by the EEPROM emulator service, before the service can be used. That is: NVMCTRL_FUSES_EEPROM_SIZE has to be set to less than 0x5 in the fuse setting, then there will be more than 8 pages size for EEPROM. Atmel Studio can be used to set this fuse(Tools->Device Programming).