Among the first questions that people ask about every new Fire TV model is if Amazon has done anything to deter sideloading apps like Kodi. Rest assured that the new 3rd-gen Fire TV Stick and the Firestick Lite can sideload apps just as easily as every Fire TV model that came before them. My Downloader app runs perfectly right out of the box on these new devices. There is just one important difference about sideloading on these new devices that may be confusing to existing Fire TV and Fire TV Stick owners.
Fire OS 7, which these two new Fire TV Sticks run, handles sideload a bit differently than Fire TVs running Fire OS 6, like the Fire TV Stick 4K, and Fire OS 5, like the 1st and 2nd-gen Firesticks. This is because of changes made by Google in Android 9, which Fire OS 7 is based on. Instead of flipping a single setting to enable apps from unknown sources, you now have to enable installing apps from unknown sources for each app individually that is doing the installing.
So if you haven’t yet installed an app that sideloads, like Downloader, you will not find the option to enable apps from unknown sources in the Developer Options menu. You have to first install Downloader and only then can you enable it to install apps from unknown sources. It’s a minor difference but it was done this way by Google so that enabling the option no longer gives every app the privilege at once. Controlling it on an app-by-app basis is far more secure. Amazon first adopted this more secure method with the Fire TV Cube 2 and we can expect all Fire OS 7 devices to use this newer method.
If you need detailed step-by-step instructions for sideloading on any Fire TV model, see my sideloading guide, which has just been updated to include details regarding the new Fire TV Stick 3 and Fire TV Stick Lite.