[Fire HD 8 and HD 10 Android Development] Eiion:
tl/dr: Solution to get Amazon Prime Video working after the tablet was toolboxed previously at the end of this post.

I'm having an issue with the Amazon Prime Video app.

Since getting the tablet (10 plus, OS Version 7.3.1.9) I've always had the recommended apps (plus a few more I think) deactivated - the Prime Video app being one of them.

Luckily I now can use Prime Video and wanted to watch on the tablet.

After manually re-activating the Amazon Prime Video app via Toolbox it gave me an error saying there was no wifi connection even though of course the tablet is connected. So I restarted the tablet, started the Prime Video app and now it's giving me an error saying "Anmeldung Fehlgeschlagen" (basically an account error with a note about problems occurring when trying to login to my account).

The thing is I'm not logged in (naturally, since I'm using the tablet toolboxed). But the Prime Video app is also not asking for my login information on the first place (unlike the prime video app from the play store on my smartphone does).

So I'm wondering... What am I supposed to do to be able to use prime video on the tablet WITHOUT having to go full Fire OS again with auto firmware update and all that when all I want is watch Prime Video on it?

Should I sideload the Amazon Prime Video app from the play store oder are there other apps I need to re-activate to be able to log in into the original Prime Video app?

And help is welcome...

Edit: Do I have to re-activate the Amazon Appstore app and login there to be automatically logged in into the Amazon Prime Video app? Would this cause the firmware to update (which is the last thing I would want) or any other unwanted issues for me, wanting to use the tablet as non-Amazon as possible?

I've been using the tablet fully toolboxed so far, everything just works (most important Steam Link) and really don't want to lose a to me (almost) perfect and Amazon free android tablet just over being able to watch prime video.

Edit 2: Installing Amazon Prime Video directly via Google play store fails. So does sideloading the app via Toolbox...

I'm out of ideas now.

Edit 3: I went ahead and re-activated the app store as well as prime video. After opening the app store there's a pop up telling me that my fire is currently not logged in to any Amazon account and that I should log in or create a new account. Though after tapping on "anmelden" to presumably login nothing happens - that loading circle just keeps spinning forever... Now I'm actually out of ideas.

Edit 4: I've re-activated Shop Amazon UT when starting the app out flashes back and forth between the home screen and a white black screen to eventually open the browser with a message saying that the Amazon Shopping App is no longer supported on this device along to use the web browser to shop at Amazon.

Edit 5: After restarting the tablet the (Shop) Amazon app allowed me to login before forwarding me to the same browser page as mentioned before. But afterwards, when opening the Prime Video app, I was logged in automatically and was able to watch videos.

I the went back into toolbox and deactivated Shop Amazon and the Amazon Appstore after which Prime Video was still working. Even after restarting the tablet Prime Video is working.

So this seems to be the solution to get Prime Video working after everything was deactivated previously:

1. re-activate Prime Video as well as Shop Amazon

2. restart the tablet

3. login to The Amazon app (this is what 'shop Amazon' is) and you should be automatically logged in to the Prime Video app as well. Open the latter to confirm

4. deactivate Shop Amazon again if you don't want it

5. enjoy!