Probably the situation with HTC's LTE patents which got Apple on the ropes: <a href="http://www.bloomberg.com/news/2012-09-06/htc-patents-challenged-by-apple-probably-valid-judge-say.html" rel="nofollow">http://www.bloomberg.com/news/2012-09-06/htc-patents-challen...</a><p>Plus HTC's downward trend recently probably made the cross-license more palatable.
Perhaps its the beginning of the end of all the litigation. It puts HTC in a useful position (although how useful that position is can't be ascertained without knowing how much they are paying everyone per handset)