3x3x4 Mixup Plus

I scrambled it. I solved it. I scrambled it. I tried some reducing. I got pretty far but decided to check on old notes. I abandoned trying to reduce the E-layer edges and followed the notes below. Here is what I found:

3x3x4 Mixup Plus Scramble

1. Thin layers. 180° on perpendicular layers; 45x° on thin layers. Some scrambling of the white and yellow 3x3s will take place.
2. White and Yellow Edges. Break up the inner edge pieces from the outer edge pieces.
3. Corners. Scramble the corners as if it were a 3x3x3.

3x3x4 Mixup Plus Solve

1. Yellow and White Centers
2. Reduce the White and Yellow Edges. Line up a white outer edge at BU with a white inner edge at FD. M up 45°, U2, M down 45°. This works well if the cube is flat. I do not know how it would be if it were shape-shifted. I shape-shifted it to see. It still works but with a little added care. Store each reduced edge in R or L. That way if a 45° turn is needed to flatten an edge piece before joining it to its edge, nothing already reduced gets messed. Use simple setup moves or the Move to move edges around.
3. Orient all the E-layer pieces. This is a simple process. Take them to the top, twist it 90°, and take it back to the E-layer.
4. Permute All Center Pieces to Center Locations Ignoring Color, Use the 3x3x2 Corner Commutator. You don’t have to turn an inner slice since the corners aren’t solved yet. 
5. Corners
6. Yellow and White Edges
7. E-layer Center Re-orientation then Permutation. Permuate using The Move, similar to solving the edges of a 3x3x2.
8. E-layer Outer Edges using the 3x3x2 method. If you get down to a single swap of corners needed hold the cube so the two that need to swap are neither on the lower left and do U R2 U R2 U R2 U R2 U. The centers are good and the corners will solve now.
9. E-layer Inner Edges. ((u 45° left) L2 (u 45° right) R2) x 2 moves A to B to C. A’s flatness stays; the flatness of B and C change. This is the 3x3x2 Corner Commutator where A is on the top layer in the front.