I just read the pages in the novel with Boba Fett's death, and he does a little more than in the final movie. He strikes me as more active. Unfortunatly we don't have a line recorded for this but as he's trying to shoot Luke on the skiff he curses at Han "Get out my way you bind fool!" He comes across in those pages as willing to defend Jabba, but really just out for himself.

So that brings up another possibility: Han knocks his rocket pack as in the the original, but he lands on the deck, leaving us to assume he gets blown up with the sail barge. If we had one more shot of him, (anybody know anyone with a movie-accurate Boba Fett suit?) he could get up and discover his rockets don't work.