Boot9.bin 3ds May 2026

In the world of Nintendo 3DS custom firmware (CFW), few files are as misunderstood, as crucial, or as steeped in technical legend as boot9.bin . If you have ever followed a modern guide to hack your 3DS, such as the definitive 3DS Hacks Guide , you have almost certainly encountered this file. You were likely told to download it, place it on your SD card, and then—for the most part—forget about it.

Everything changed in 2018. In early 2018, a hardware hacker known as derrek (with contributions from others like nedwill and plutoo) made a monumental breakthrough. Using a low-level glitching attack (specifically, a voltage fault injection attack known as "the DSiWare glitch" combined with an intricate understanding of the 3DS’s memory layout), they managed to extract the entire BootROM 9 from a physical 3DS console. Boot9.bin 3ds

No system update from Nintendo could fix it because the vulnerability wasn't in the software; it was in the immutable hardware (the BootROM). The only way to remove boot9strap from a 3DS is to physically replace the CPU. In the world of Nintendo 3DS custom firmware

But what exactly is boot9.bin ? Why is it required for every single modern 3DS hack? And why do security experts and console modders hold the number "9" in such high regard? Everything changed in 2018

The result was a 32-kilobyte binary file named .

So the next time you boot your CFW 3DS, scrolling through your library of CIA-installed games, take a moment to thank the little file sitting silently in /boot9strap/ . Without boot9.bin , your 3DS would still be locked in Nintendo’s plastic prison.

This was not a hack. This was a dump of Nintendo’s master key material. With this file in hand, security researchers could disassemble the literal root of the 3DS operating system. They found what they were looking for: the and, more importantly, the Boot9’s private keys (or methods to derive them).