The BootROM contains Nintendo’s root of trust—private keys, cryptographic hashes, and validation routines. No software exploit can permanently alter it. However, in 2017, a monumental event changed everything.
boot9.bin is a raw dump of the internal boot ROM (Read-Only Memory) embedded directly inside the 3DS primary processor (ARM9). The ARM9 Processor
This is the most common method for users running boot9strap .
The 3DS relies heavily on AES encryption to protect games, save data, and system firmware. The actual cryptographic master keys are hardcoded inside the Boot9 ROM. During the boot process, the Boot9 code takes these keys and writes them into the ARM9's hardware keyslots. 3. "Locking" the Keys