The file boot.firm
is what is launched by boot9strap itself after it finishes loading off of NAND, and can be any valid arm9 payload in the FIRM format. This file can be replaced at any time, although Luma3DS allows for the launch of other arm9 payloads in the FIRM format using the Luma3DS chainloader.
In this case, we use Luma3DS by AuroraWright to boot a patched SysNAND directly, allowing us to completely bypass the need for any kind of EmuNAND, vastly simplifying the usage of a hacked 3DS in addition to saving SD card space.
During this process, we also setup programs such as the following: