Are you trying the screencast with a device that's already been BT paired & connected to your Glass? I never see the barcode option, it just connects straight

Are you trying the screencast with a device that's already been BT paired & connected to your Glass? I never see the barcode option, it just connects straight to my device immediately. I think you only end up with the barcode if you're not connected or having connectivity issues. Google posted an update yesterday to the MyGlass app that supposedly improves connectivity, so maybe that might solve the trouble you'd been having.