MsMocha:
Will setting the high fuse (EESave) via board.txt will help me to maintain the EEPROM value after new program upload?
Yes. Only the flash will be erased, the EEPROM will not.
MsMocha:
Yes, I would like to learn how to create customized board.txt.
Which version of the Arduino IDE are you using?
MsMocha:
However I'm using macbook, is the steps going to be similar?
They are the same.