Return of the Ewok was a short film made during the shooting of ROTJ by David Thomblin, (1st assistant director on ROTJ) .
This is how Warwick Davis (Wicket, who is the "star" or Return of the Ewok) described the short film in interview:
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"It's actually about me, age 11, trying to decide on a career. I try soccer and weight lifting at Dave Prowse's gym before finally being inspired to 'be in the movies' when I see Mark Hamill outside a movie theatre in London. The scene plays out like this: I am looking at movie posters of 'Empire' outside a movie theatre, the fight between Vader and Luke is shown, and at the point when Luke backflips out of the shot, he lands outside the movie theatre in London . I tell him - 'Go back, you can do it!'. He agrees, goes back in, and continues the fight with Vader. Highlights of the film include me wearing Boba Fett's outfit, Wicket visiting Yoda to get his intergalactic passport. There is a scene between Wicket and Darth Vader in the Emperor's throne room, and a great moment when Wicket visits the dressing rooms of Carrie Fisher, Mark Hamill & Harrison Ford."
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A short excerpt from the film was seen in the hidden extras on the recent DVD box set, featuring Boba Fett hunting Warwick onboard the Death Star set...
If you have the full-length version, Morridini, I'd certainly be very interested in getting hold of a copy...