I have bought TDuk’s doctor cache cleaner (from amazon(, works really well on my cube. I thought I should load it on on fire-stick 4k. Can’t do it. On amazon the only options are my cube and cloud. so i selected cloud, and tried to sync device on 4k nothing happened. Tried physically copying the apl to cloud nd from cloud back to 4k - get parsing error. So why can i not download onto 4k. When i check on manage devices it is there!
I had the same problem. This app only works on Amazon devices using version 7. The firestick 4k uses version 6 so far as I can remember. I now have a 4k max and the app works fine with it.