In Legends, it was theorized that the Death Star had:
One hundred twenty-three individual hyperspace generators, tied into a single navigational matrix (...)
were necessary to carry the Death Star beyond the speed of light.
I believe it was in a legends book (perhaps Crosscurrent, where big ships had multiple hyperspace generators) that was mentioned that parts of a ship could be separated in hyperspace and end up in unexpected places, different time-space or even be stuck in hyperspace permanently.
Therefore, what would happen if this "matrix" was compromised and one or several of these hyperspace generators failed while jumping to or while in hyperspace? Would chunks of the Death Star be left behind while others make the jump?
Sidetracking... The Rebels would just need to hide in some ship's smuggling compartments, dress up in knocked out stormtroopers suits and force a failed hyperspace jump, maybe with the help of an old Jedi and some luck, thousands of Bothans would be saved...