They definitely had not given up hope on the mobile phone business when they chose Windows Phone. At the time they were still one of the largest phone manufactu

They definitely had not given up hope on the mobile phone business when they chose Windows Phone. At the time they were still one of the largest phone manufacturers and would have probably stayed relevant to this day if they had chosen Android. Microsoft told them all sorts of bulls*hit about how Windows Phone was as good as Android or at least was going to be by the next version. They thought it was plausible that together with MS they could break the Apple-Google duopoly, and since MS gave a massively sweeter OEM deal than Google, WP it was. Note that the board fully supported Elops actions at this point, it was not a backroom deal. Once Nokia engineers got to actually working with WP they found out it was technically in far worse shape than MS had led them believe, but at that point it was too late to backpedal to Android. It took almost half a decade and four huge upgrades (WP 7.5, WP 8, WP 8.1 and W10) before WP became somewhat competitive to Android, but that was much longer than what Nokia could reason financially, so the best option left was to ditch the sunken phone business to the highest bidder. Microsoft was luckily still believing they could break the duopoly so Nokia again got a pretty sweet deal from them.