if you're using Gateway's arm9loaderhax, restore and older NAND dump to sysnand (hold up and select "downgrade"), and switch to a standard arm9loaderhax fork instead of GW's(you should have otp.bin to use with SafeA9LHInstaller). also use Luma3DS instead, because rxTools does not support arm9loaderhax and does not get updates anymore.
If I don't have a nand dump from before doing the method on this thread, this can't be done?
I was hopping this would be way easier like swapping the boot.3dsx (from gateway) for ctrmanager boot.3dsx or something. :/
Also when you say another fork, you mean like homemenuhax? I would have to do the entire installation process?