There is one known drawback of Open Mode on N9, and that is that device lock does not work on Open Mode. (however there is a correction to that problem: http://talk.maemo.org/showthread.php?t=92465) As for facebook account asking for password, this means that you probably did not do the back-to-back flashing quick enough; If the device does boot between the flashings, then you get to this state. There are 2 solutions to this problem:either you need to do back-to-back flashing again or else you can try to delete the aegis keys from your home directory (but this may not rid you of all the problems)