The problem solved with youtube videos :) For some reason, Youtube videos don't play in mobile format, as the message says "format is not supported". To solve this problem, we need to switch to desktop mode on the bottom on the left side menu and the videos start playing. Of course in Desktop mode the resolution is too big for the mobile screen, so we need to switch to full screen. Would be nice if someone who using a Firefox OS mobile, could confirm that if this desktop switch is necessary (or works) in a real device too or only in simulator. But even more interesting, this method also works without the actual youtube app. If we switch to Desktop mode, the youtube videos can be played straight inside the browser without need to install the youtube app. When we start a video, it says only for a second, wee need to install adobe flash plugin, but after a second the video start playing anyway XD. I'm really can't decide if it a glitch with the simulator or what. But flash videos works only on youtube this way, on other sites flash videos don't play. So if anybody is here who own a real firefox device or anybody from the development team, would be great if can be confirmed if we can play youtube and\or any flash content in Firefox OS or don't. Probably I'm going to buy a ZTE Open anyway as I'm using the simulator more, I like it more, but would be great to know what is the situation with flash and youtube on real devices. Thanks.