I'm still trying to find out what happened to The Empure Strikes Back in the theaters between the time I saw it the first week it came out, and then three months later. I distinctly remember Yoda riding in Luke's backpack, throwing rocks in front of him for his lightsaber. That scene disappeared in a later theatrical version, yet I remember seeing it.
BTW, did the scene with Luke using R2D2 as a fire hydrant for washing off his X-wing ever reappear in any version? Or did I imagine that scene, too?
I remember Yoda riding on Luke's back, but not throwing rocks...