Boot9.bin - File

It contains console-unique data? (Actually, BootROM is identical across all consoles of the same model, but sharing it still exposes Nintendo’s proprietary code.)

The BootROM is a small, read-only memory chip embedded directly into the CPU (the ARM9 and ARM11 processors) of the 3DS. This memory is physically programmed during the manufacturing process at Nintendo’s factories. It cannot be erased, rewritten, or modified by any software means. It is the "first code" that executes the moment you press the power button. boot9.bin file