A dead-simple, step-by-step guide to unlocking ADB debugging and sideloading apps on Amazon Fire TV devices.
Install APKs that aren't available on the Amazon Appstore.
Connect Android Studio or ADB over Wi-Fi for development.
Access system-level tweaks, overdraw, and GPU profiling.
From the Fire TV home screen, navigate to the far right and select the Settings gear icon using your remote.
Inside Settings, scroll to and select My Fire TV. On some newer models or software versions, this may be labeled as Device & Software or Device Options.
Within the My Fire TV menu, scroll down to About and select it. This screen displays your device name, network info, and software version.
Highlight your device name (usually says "Fire TV Stick" or similar) and press the OK / Select button on your remote 7 times rapidly.
A toast notification will appear counting down: "You are now 4 steps away from being a developer". On the 7th click, it will say "You are now a developer!"
Press the Back button to return to the previous menu. You will now see a new option called Developer Options listed in the menu.
Open Developer Options. Find ADB Debugging and turn it ON. This allows your Fire TV to accept connections from Android Debug Bridge tools over your network.
Still inside Developer Options, find Apps from Unknown Sources (or Install Unknown Apps on some newer versions) and turn it ON.
Developer Options are now unlocked. You can install third-party apps, use ADB wirelessly, and tweak advanced system settings.