I wouldn't get too hyped up for SoH on 3DS as the WiiU already struggles to handle it when you go beyond that the original game could handle (such as higher FPS, mods, etc...) And well, OoT3D works very fine for this
If that's the place I'm thinking, it's hidden in a Yellow Toad block below the central place (You don't need Yellow Toad to get it but it helps greatly)