Change the cable and power adapter
This primarily affects Fire TV Sticks, but a bad micro USB cable or power adapter could also be to blame. however, try switching out the micro USB C cable that is currently attached to the Fire TV Stick if you happen to have another one. Try switching out any USB power adapters you might have as well. Any phone charger and micro USB cable should function. While you’re at it, you might as well try a different power strip or outlet.
Wait a very long time
There’s a slight possibility that your Fire TV is trying to finish a bootup task that is simply taking a long time to complete. Turn on your Fire TV as usual, and then wait at least a few hours or even a day for the logo to become stuck.
Factory Reset with a USB keyboard
It’s worth a shot to try this solution even though it might only work with older Fire TV models, especially if you already have everything you need. You’ll need to attach a USB keyboard to the Fire TV in order to test this. This means that you require an OTG cable in order to use a Fire TV Stick. If you already have a way to connect a USB keyboard, then use these instructions to try a factory reset.