Hi, I'm trying to stream Prime Video on my MBP (15" 2013) and MBA (11" 2011) to my screen and beamer via Minidisplayport and HDMI 1.4. Strangely, Firefox (and also Chrome) refuse to show HD quality saying that the Mac (or equipment) does not comply with HDCP requirements (showing only SD quality), although I found out that Safari reproduces HD quality flawlessly. I enabled DRM, Safe Mode, etc. and the problem only occurs when I connect to my screen or beamer (both HDCP compliant, and the cables too). Looks like a compatibility issue. I'm running Firefox 67.0.4 (64-bit) on MaOS Sierra. Your help is appreciated, as I would like to keep using Firefox as my main browser...