SigHax/Boot9Strap Roundup Info Thread
The latest advancement in the 3DS homebrew scene is here: SigHax, and Boot9Strap. Thanks to the 3DS's bootroms being dumped, SigHax/B9S allows for CFW to be run instantly after the execution of the bootrom. This opens many doors for homebrew developers, and the scene in general.
Sighax is an exploit discovered by derrek, where he used a dumped copy of the bootrom in order to have every custom firmware be read as valid during the verification part of the 3DS power-on sequence.
Thanks to @icefire82G
Sighax.com is moreso designed for developers, rather than the end user. If you wish to ensure the safest way of installing this method, use Boot9Strap, via the safeinstaller. It appears that SigHax has a high brick chance, comparatively. (The above 3DS.guide uses the safer B9S)
Thanks to @Lia
All future releases of Luma3DS will only be made in the .firm format, which will only be compatible with boot9strap and sighax. This means that to continue receiving the latest updates of Luma3DS, you should use this page to update your installation.
If you have any corrections to offer, please PM them to me, and I will update the OP to the best of my ability.