B button suddenly doesn't work on my 3ds

My b button suddenly doesn’t work after i charged it up, it was working fine before when i last used it but when i used it again after charging the b button just doesn’t work. I have tried replacing the button board with another one that works fine on my brothers 3ds but still the b button didn’t work. So is this some sort of a software problem? because i have homebrew and cfw installed. Do i need to do a factory reset? or is there another way to try and fix this problem?