You can set shumway.disabled to true to disable it in Firefox or open the add-ons manager about:addons to disable or remove it from there. It is possible to disable Shumway in two different ways. It is only enabled for Amazon Video currently and while you can theoretically change that to the * wildcard symbol to run Shumway on all sites with Flash contents, the vast majority of them won't play as Shumway is still a work in progress. The paramter lists all sites and destinations on the Internet on which Shumway is being used instead of Adobe Flash to load Flash contents. Video playback is controlled by an about:config parameter currently. The video area itself remains black however no matter how long you wait. Any attempt to play instant or prime videos fails currently even though the Shumway box is displayed on the screen. This confirms that Shumway is being used to play the video and not Adobe Flash.
