If you’ve spent time with Nintendo DS emulation, you’ve probably encountered a small but crucial file: nand.bin. That single binary contains the emulated console’s internal NAND flash — the DS’s on-board storage — and it’s essential for running some games, enabling save functionality, and reproducing system behavior faithfully. In the melonDS emulator, nand.bin plays an outsized role: it’s where system settings, firmware data, and certain game- and homebrew-dependent content live. Understanding what nand.bin is and how melonDS uses it gives you insight into why some titles behave perfectly while others don’t.