The process is quite straightforward, however, you want to follow the steps carefully as mentioned in the manual so that you don’t encounter errors at a later stage.
I will demonstrate how you can upgrade Kodi on FireStick or Fire TV without using even a computer. If you’re using an older Kodi version (latest version as you may know is Kodi18.4 Leia) in your Fire TV / Stick, this guide is for you.