you asking how to preveng cfw from installing? or prevent the (unlikely) risks?and how to prevent it from happening?
At the moment, there is absolutely no risk with a zero percent chance of bricking. The catch is though, you can only install cfw for free on firmwares 11.3 and under. If you want cfw for 11.5, you need either a compatible ds flashcart listed on 3ds.guide or a second 3ds on a lower firmware to system transfer with. Flashcarts average to about 20 dollars each.What are the risks of installing a CFW for Old2ds running Ver11.5 (Luma3DS) and how to prevent it from happening?
(Using method 3ds.guide)
At the moment, there is absolutely no risk with a zero percent chance of bricking. The catch is though, you can only install cfw for free on firmwares 11.3 and under. If you want cfw for 11.5, you need either a compatible ds flashcart listed on 3ds.guide or a second 3ds on a lower firmware to system transfer with. Flashcarts average to about 20 dollars each.
prevent the risksyou asking how to preveng cfw from installing? or prevent the (unlikely) risks?
theres the extremely rare chance of a brick when installingAt the moment, there is absolutely no risk with a zero percent chance of bricking. The catch is though, you can only install cfw for free on firmwares 11.3 and under. If you want cfw for 11.5, you need either a compatible ds flashcart listed on 3ds.guide or a second 3ds on a lower firmware to system transfer with. Flashcarts average to about 20 dollars each.

And I add more that every soft bricks is always fixable via flashcard.theres the extremely rare chance of a brick when installing
He wont hard brick using NTRboot flashcart installation, and should he somehow softbrick he can repair it with it.theres the extremely rare chance of a brick when installing