Hopefully someone will find this blog post extremely helpful. Tonight I purchased an Amazon Fire TV Stick with the intention of building a cool new React app for the Fire Stick. My hacking session started off well, but I soon ran into an awful bug where my Fire Stick would continually display nothing but a black screen for my React app when using the Web App Tester.
Well after two hours of struggling with this issue, I discovered the solution to this problem: You cannot use a white background color when developing HTML5 apps for Fire TV Stick. All I had to do to get my app to start working was change the background color to purple!
When starting a new project developers tend to start with a blank canvas and a little black text, but this will not work on the Fire TV Stick. So if you find yourself running into a similar problem where you just can’t get your Fire Stick to display your Hosted HTML5 app using the Web App Tester, try changing your background color to something other than white.