**If you are unable to follow the instructions corresponding to your specific version due to missing prerequisites, then you should either update to the latest version or use the "All Versions" row for methods that work regardless of system version.**
For all versions you can also [Cartridge Update](cart-update) (or use a standard system update) to get to a higher version in the same column to follow its instructions.
If you have already hacked your 3DS before and have an EmuNAND based CFW setup, just follow all instructions while on SysNAND. Replace any files that already exist. Your data will be transferred from EmuNAND to your new B9S install at the end. If you use menuhax, you should [clear Home Menu's extdata](troubleshooting#clear-home-menu-extdata) to remove it before beginning.
This page is for instructions on how to install boot9strap to a *stock* 3DS or 2DS. If you already have arm9loaderhax installed and are looking to update to boot9strap, follow [A9LH to B9S](a9lh-to-b9s).
Before starting, Windows users should enable the option to show file extensions using [File Extensions (Windows)](file-extensions-(windows))!
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Before starting, you may want to check your SD card for errors using [H2testw (Windows)](h2testw-(windows)), [F3 (Linux)](f3-(linux)), or [F3X (Mac)](f3x-(mac))!