So the Falcon using a backp hyperdrive is speculation bases on WEG SW?
That's not how I would put it. Keep in mind how canon works in Star Wars. At the top are the movies. They trump everything. As far as I'm aware they never mention backup hyperdrives, so if the movies are all you want to consider for Star Wars, any theory of yours is perfectly valid.
The second tier of canon consists of official TV shows, most notably the Clone Wars cartoon. As far as I'm aware backup hyperdrives are never mentioned here either.
The third tier becomes more interesting. This is where the EU is introduced. The EU, to a large degree grew out of the West End Games RPG. The RPG was so thorough and so popular that Star Wars authors used it as a reference. As a result, you can consider the West End books to be a kind of lexicon to the EU, the innermost source so to speak. They are the first source to mention backup hyperdrives, and just about every ship has one. As far as EU sources go, this is as official as it gets, and it's certainly not speculation. If you want to dig up the source yourself, Wookieepedia refers to Star Wars: The Roleplaying Game, First Edition pages 54-58 when talking about backup hyperdrives.
For the record, there are two more tiers of canon below EU. These are (in order of importance, high to low) secondary canon (stuff like Star Wars Galaxies and the Old Republic MMO) and finally non-canon (such as Han Solo dancing in the Star Wars Kinect game for Xbox 360).
Edited by TiLT, 12 July 2013 - 09:08 AM.