It is convenient to have a simple file system for use on the SPI EEPROM or RAM, to allow a number of wave tables, WAV files, or other files to be assembled on a host and then written to the EEPROM as one file.

The NASA developed EEFS is a good solution for this need, but it was developed with 32 bit machines in mind. The AVR ATmega uses 16 bit pointers, and so there needed to be some changes.

Implementing NASA EEFS on AVR ATmega