If you've hacked your 3DS via boot9strap and Luma3DS I'd recommend just following the guide along again to get your homebrew setup sorted out again, particularly the Finalizing Setup page walks you through the process of installing FBI properly.
Though I would also recommend double checking all the firmware files for luma are all in the right places according to the guide.
Though I would also recommend double checking all the firmware files for luma are all in the right places according to the guide.