The firmware 11.4 and reinand work better than firmware 11.13 and luma IN GRAPHICS 3D WHEN USING SUPER-STABLE 3D OFF.
For DOWNGRADE TO 11.4 "sysUpdater" and go back to 11.13 with update the n3ds all time, this is not hard.
For LUMA or REINAND you can use them separately folders in the memory...