Follow the quick steps below to get Developer Options back:
1. Highlight Settings on the FireStick home screen
2. Open My Fire TV.
3. This is the window where you would typically see the Developer Options. However, it’s not there. Therefore, it must be enabled. Click the option About.
4. Select your FireStick on the next window. For example, I have Fire TV Stick 4K.
5. Quickly click your FireStick 7 times and the following notification appears at the bottom of the screen: No need, you are already a developer.
6. The Developer Options have been reinstated.
7. When you click the Developer Options, the two settings appear: ADB debugging and Install unknown apps (some devices may show Apps from Unknown Sources instead).
Now, you can go into Developer Options and enable Apps from Unknown Sources to sideload APKs on your FireStick device.
Select Install Unknown apps.
Congrats! You have now officially “jailbroken” your Fire TV Stick.