I have flashed my ZTE Open to FFOS 1.4 with this method (http://xdaforums.com/showthread.php?t=2680514), only some bugs - AND: How can I root the ZTE, this method ( pof.eslack.org/2013/07/05/zte-open-firefoxos-phone-root-and-first-impressions) don't work. My before 1.2-prerelease-version was rooted of course.