I got an efficient EEPROM library “EMULATED” in Internal Flash of STM32 (The space between Bootloader and System Flags). Max 255 bytes. Configurable using EEPROM_SIZE define.
https://github.com/spark/core-firmware/tree/feature/flash-eeprom-emulation
Provided Arduino APIs : EEPROM.write() and EEPROM.read() for accessibility.
Planning to add conditional compilation code for CC3000 NVMEM as an alternative if that helps.