User Agent: Mozilla/5.0 (Windows NT 5.1; rv:36.0) Gecko/20100101 Firefox/36.0 Build ID: 20150320202338 Steps to reproduce: I'm trying to test an application using "PowerManagement" API, specifically with the "powerOff" method. This API requires "power" permission and "certified" type apps specified in the webapp.manifest file. I also correctly configure my device following this link https://developer.mozilla.org/en-US/docs/Tools/WebIDE Actual results: I want to shutdown my device using this code: - var power = navigator.mozPower; power.powerOff(); - unfortunately only works on WebIDE simulator and B2G Desktop, not in FFOS 2.0 device. Why my device doesn't turn off? What am I doing wrong?