First I had the 0% bug while trying to update from PR 1.1. Then I downloaded Nokia Software Updater and upgraded to PR 1.2 After the first reboot I had the "refreshing cache" bug after I first upgraded to PR 1.2. To make things worse I also had the "impossible to enable Developer Mode" bug so I wasn't able to access the Terminal to debug. My solution was to reinstall PR 1.2 using Nokia Software Updater... 3 times! Yes, you read it right: my N9 only went back to normal after I reinstalled PR 1.2 via NSU for the third time! I hope it works for you people.