How to run GameCube games on Dolphin without an SD card slot or any form of external storage device? Is it possible to store save data in memory instead - Quora
Load games off SD-card - withouth modding? : r/Gamecube
Nintendo GameCube – Wikipédia
Gamecube GC Loader PNP Copying Saves to a Virtual Memory Card with Swiss & SD2SP2 | How To Guide - YouTube