When you play a DS game on original hardware, the game sends commands like "play this sound effect" or "read the X,Y coordinates of the stylus." The ARM7 BIOS translates those commands into physical actions. Modern PCs are vastly more powerful than the Nintendo DS. So why can’t an emulator simply "fake" the BIOS functions?
Emulators themselves are legal because they are original code. But distributing the BIOS file alongside the emulator is piracy. dsi bios7.bin
Specifically, bios7.bin contains the boot routines and interrupt handlers for the ARM7 processor. Think of it as the firmware instruction manual for that secondary chip. When you play a DS game on original
The only legal way to obtain bios7.bin is to using specialized homebrew tools (like nds-bios-dumper ). This process involves running a small program on a modded DS to extract the BIOS data from the hardware. Emulators themselves are legal because they are original