iPhone 4 Power & Lock Button Replacement
Dealing with the right screw is really a pain in the *^#... I think it's quite easy to damage the ribbon cables covering it.
iPhone 4 Front Facing Camera Replacement
I agree, steps 20 and 21 are completely useless. In fact I found it hard to remove the metal cover, so just skipped it, seeing that it shouldn't affect the button. And it didn't. I also think these steps should be removed not to cause the confusion.