1. Type 'about:config' in the address bar. 2. Type 'plugin' In the search bar on top. 3. You should see some options popup. 4. Need to change these 2 (scroll down a bit): plugin.default_plugin_disabled and plugin.disable 5. Tap on each one (or use the arrow keys) and hit enter. This will change the value from true to false. 6. Close Firefox and restart.