A bootloader for the 3DS console, written by derrek, profi200, d0k3.
fastboot3DS is a bootloader for the 3DS console, intended to be installed to the FIRM0 partition. It allows you to assign homebrew in .firm format to bootslots, and to chainload bootslots via either a bootmenu or a button combo of your choosing. fastboot3DS also contains basic tools for NAND backups and restores.
fastboot3DS installs to a critical partition of your system, and thus becomes one of the softwares critical to the functioning of your system. Although having been thoroughly tested, some risk may still remain, especially when fastboot3DS is not used in the way it is intended. In short: we are not responsible for any damage that may occur to your system as a direct or indirect result of you using fastboot3DS.
Quick start guide
These short instructions require you to have a way of booting OpenFirmInstaller. If you already have boot9strap installed, this is as simple as chainloading the OpenFirmInstaller.firm (either via some chainloader of your choosing, or put it on your SD card as sdmc:/boot.firm).
Have fastboot3DS.firm inside the sdmc:/ofifolder on your SD card. When installing from A9LH, secret_sector.bin is also required.
Boot OpenFirmInstaller and follow the on screen instructions. You will reboot to the fastboot3DS menu.
[optional] Enter Boot setup... -> Setup [slot 1]... -> Select [slot 1] firm and select the FIRM file of your main CFW. On typical systems that is smdc:/boot.firm, but anything goes.[optional] Enter Boot setup... -> Change boot mode... -> Set quiet boot. Your system is now set to autoboot and will silently boot the CFW you selected above.
You may also want to set up the other boot slots and assign key combos to them. Keep in mind you need one autoboot slot (= a slot with no key combo assigned). If you want to access the fastboot3DS menu at a later point in time, hold the HOME button when powering on the console. From the fastboot3DS menu, you may continue the boot process via Continue boot, chainload a .firm file via Boot from file..., access the boot menu via Boot menu... or power off the console via the POWER button.