If you use the Beginners' Method to solve the Rubik's cube, and solve the equator layer (the layer between the U-layer and D-layer), it can happen that one of the edges is flipped, like this:

Rubiks Tilt - Kerrison Toys Rubiks Tilt - Kerrison Toys

If you're manoeuvres to swap two corners and twist three corners on your final layer do flip edges, you could use these and their reflections instead: Swap 2 corners: R U' L' U R' U' L Do what you do to move an edge from top layer to middle layer, i.e. U R U' R' U' F' U F or U' F' U F U R U' R'. Note. This is in fact only one formula, but the others are the inverse and mirror image along the FR-plane. This answer was given by Emrakul. I would suggest starting to look ahead (which you might do earlier than this, but could do here), you know you will want all the top (as you show) edges to have the correct flip, this would be an ideal point at which to start combining your efforts - your method most likely does the corners next, but it is most likely that the manoeuvres you already use do not flip the edges*. Build your own LEGO® MINDSTORMS® robot to solve the Rubik's Cube®... How to build MindCub3r for LEGO MINDSTORMS EV3If you watch the piece this takes the two of them, splits them rotates them, and aligns them reorientated on the top layer. U U Ri Fi U U F