Following directions found here: https://hacks.mozilla.org/2014/01/upgrading-your-zte-open-to-firefox-1-1-or-1-2-fastboot-enabled/comment-page-1/#comment-2157666
I entered a boot loop. Infinite looping. I read that this could be escaped by holding Vol+Up & Vol+Down then plugging in a usb drive while the battery is removed. This should bring up a button, however it did not for me.
Does anyone know how to salvage the OS from a boot loop?