The boot9.bin file is a backup dump of the ARM9 BootROM firmware from a Nintendo 3DS, which serves as the "root of trust" for the system's security. This file contains the foundational RSA public keys and cryptographic functions used by the ARM9 security processor during early system initialization. The Role of Boot9.bin

• You will see a warning about writing permissions. Press (A) to continue if prompted.
• Look for a file named boot9.bin or sometimes boot9_prot.bin. It might be visible immediately or inside a folder depending on your setup.
• Note: Modern versions of GodMode9 often display these files in the root of the drive screen under a special "Memory" section or inside the SYSNAND drive directly.

Custom Boot Animations

With boot9.bin, you can modify the boot splash screen by patching the BootROM’s graphics output—though this is extremely advanced and risks permanent brick.

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Step-by-Step Dumping Process

Once your CFW is functional, here is the safest method: