Originally Posted by mohzean
Thank you so much for your help, now I have version 4.5.2 working successfully, although update does not work, giving me error "Last update failed"
I rooted using Kingsroot and installed Safetrap.
Let's leave well enough alone. Can revisit 4.5.2 -> 18.104.22.168 update should you wish to install a custom rom in the future. Strongly suggest you not attempt to install any variation of Google Play Services and/or Play Store with FireOS v4. Outcomes are variable but almost universally unsatisfactory depending on pain threshold. Custom ROM is the best path if you find Amazon's offerings too limiting.