How to solve a Rubik's cube 4х4 - Step 9
In the beginning of this step, the corner pieces of the up face should be in their places. At the same time, they can be turned wrong.
In the end of the step the cube should be solved completely.
To turn the corner pieces by the right side, use algorithm from the 7th step for the cube 3x3 You can have one of the following pictures. All corner pieces of the up face are turned wrong or
This sequence should be repeated till the right piece of the up face will turn properly. At the same time the cube can ''break''. Don't be scared. If you repeat the sequence few more times, everything will be in place. Only before the repeating of the sequence, you should place another ''wrong'' piece to the right corner. Depending on the case, you need just to turn the up face necessary number of times to place the ''wrong'' piece into the right corner.
In case a) rotate the up face once
In case b) rotate the up face in any side
Now carry out the sequence to turn this piece right.
In the end your cube should be solved!