The Peacock app for Fire TV devices is now available in the Amazon Appstore. NBCUniversal and Amazon said the app would “be compatible with the entire Fire TV product line-up” but that is unfortunately not the case. The app is not currently compatible with the 1st-gen Fire TV or the 1st-gen Fire TV Stick. I haven’t tried it myself yet, but if you would like to try sideloading the official Fire TV version on those devices, you can enter
The sideloaded version of Peacock, which was pulled from Android TV devices, has a different package name than the version released today for Fire TV devices. This means that the official Fire TV version will not overwrite or update the sideloaded version. While this does mean that you can technically keep both the sideloaded and the official Fire TV version of Peacock on your Fire TV simultaneously, there’s not much reason to do so.
If you have the sideloaded version of Peacock installed, you should uninstall it before installing the official Fire TV version. If you need them, instructions on how to uninstall apps can be found here. Once the app is uninstalled, search for “Peacock” on your Fire TV and install it from the Amazon Appstore. Note that you will probably need to scroll a bit to the right to find the official Peacock app when you search. For me, it was the 10th app on the list when I searched for “Peacock.”