where to store sound files(*.DAT) on board without SD card

Hi all!

I intent to make small prj about make sound on RL78G14 Demo Board as the following link(sorry, it's only japanese version)

https://www.youtube.com/watch?v=lkArk4Gwuxk&list=PLgUXqPkOStPuziLqRF-w0Qy68CyScnZnS&index=3&t=0s

 

The problem differ from above link is I do not have SD card for store *.DAT files, so I think I can store them at somewhere else on board.

and how to do it?

Thanks a lot