I'm working on Chris Hardwick's method for the 4x4x4 found here:

http://www.speedcubing.com/chris/4-solution.html

I've got it all down fine except for the case when there's a parity error in the final step of orientation on the top layer. If a corner is flipped or two opposite edges are flipped he gives the following algorithm to flip it in place:

r2 U2 r2 U2 u2 r2 u2

I have tried this hundreds of times and every single time it fails to work. I just end up with a slightly jumbled cube. The other parity error, a single edge flipped, has an algorithm and it seems to work just fine for me but this one does not. Is there a typo somewhere? I am 100% sure I am doing the moves correctly.

Thanks for any help you can give me.

When you do the lower case r's and u's, are you turning both the face and the next one in? (i.e the 2 rightmost faces when it says r and the 2 uppermost faces when it says u)

You should only be turning the middle face if it is lowercase. When it says U2 u2 in the algorithm, that is when you turn both of the top 2 faces.

On the 3x3, lowercase letters mean to turn 2 faces, but once you get to larger cubes, 4x4 5x5 etc., it means to only turn the second layer in.

Hope this helps.

(Rr) means turn the 2 right layers clockwise. r means the inner right slice
clockwise. Just some examples.

hmm, well that's what I have been doing. Lower-case means turn half the cube (as opposed to just a single layer).

I just tried again, making absolutely sure that I was doing it correctly and it just got jumbled. I think I might upload a video to show what's going on...

But thanks for the responses.

I don't know if that is what you meant to type, but what we have said is, lowercase DOES mean to turn only one layer, and that one layer is the inner slice on that side. The outer face stays where it is if it is a lowercase letter.

If you are doing the 3x3 cube, then it is turning 2 faces, on every other cube though, it means only turn one layer.

Hmm? lowercase doesn't mean turn half the cube it means turn an inner
slice. A lower and upper case in () means turn half the cube like a 2x2.

here

The alg is r2 U2 r2 (Uu)2 r2 u2.

i posted the quicker way to do it if you have a lock up cube. please don't sue me, i can't afford it.

Ok, I figured out what I was doing wrong...

All you guys were correct, I completely misinterpreted what the lower-case notation meant. Once I saw the video (which I must thank you for posting, it was very helpful), I understood that it was just turning the inner layer (which, incidentally is exactly what the description says on Hardwick's page).

The funny thing is, for all the other steps where there is a lower-case I have been turning half the cube and in fact I memorized all those steps that way. I have had no problems with doing this until this last step so I guess it doesn't make too much of a difference on the steps that I did this on. This is probably because there is no change on the outer layer for those steps so flipping both doesn't make a difference.

But either way, thank you all for helping me, I appreciate it.

And what is a lock up cube? I've never heard the term.

some cubes lock up alot when you try to flick an inner layer. so it is easier to do Uu2 U2 rather then u2.

if you want to see any applets of algs performed check out bigcubes.com