[Fire HD 8 and HD 10 Android Development] RoidBoy:
2 AMAZON ACCOUNTS ON 1 TABLET, PLUS FULL ALEXA FUNCTIONALITY:

My family shares a Prime account, for watching PRime movies and getting free shipping etc, but I also have another non-Prime account that I use to control my lights, echo devices etc around my apartment. I want to share some information that may be helpful to someone out there who wants to have BOTH accounts available on your Fire HD 10 Plus. My software is 7.6.2.1. , purchased new on ebay in Dec 2022.

I also am using an older Samsung wireless charger, which means that the Fire HD 10 + acts like an Alexa (or Echo) device when sitting on the charger. My problem was that, as an Alexa device, it wasn't controlling my lights with my voice commands, as all other Echo devices do in my home. The solution was my doing a factory reset, then using Fire Toolbox to turn off OTA updates, but leaving all Amazon apps and Fire Launcher untouched UNTIL I registered the tablet under the acct which is my personal Non-Prime acct, under which all of my Alexa devices are controlled. Although I actually had to do a factory reset more than once to get the Alexa app to respond properly to my voice commands, it did work fine eventually. ONLY then did I add another Amazon acct to my tablet, so that I could enjoy and download PRime movies, Audible Library books that I purchased using the PRime account, etc. You add the second Amazon acct by pulling down from the top of the screen, pressing the icon shaped like a person, and then adding the email and password of the PRime account. It turns out that the Tablet can ONLY have one fully functional Alexa device on it, and that is why the FIRST registration MUST be the one corresponding to all of my Alexa devices in my home.

Interestingly, once I switched accounts to the Prime account on the tablet, Fire Toolbox was able to make some more modifications, such as removing a lot of unnecessary Amazon Apps, changing keyboards (again - as I had already done this when setting up the original registration account, and some other mods. Google services was, seemingly, already on the second account, as the Fire Toolbox didn't give me the option any longer to install it. The Playstore app is not seen in the Prime acct, but this doesn't bother me, as I will ONLY be using that account on this tablet for possibly PRime movies, Audible, and Amazon Prime shopping, and everything else I will do from the FIRST registered account.

Now that Both accounts are registered, I found it didn't mess anything up to use Fire Toolbox to remove some bloat Amazon software from both accounts... If you remove too much Amazon before registering, you may find that registering accounts is greyed out, and not an option.

Now my tablet works perfectly as an Alexa device when I'm in the non-prime acct, and when I'm in the 2nd acct (PRime) it does show and download the movies to the sd card. NOTE: I did have to call Amazon and talk to the Alexa App department, and asked them to make a family group by combining the 2 accounts together! Otherwise I don't believe this will work as described above. The one downside is that now when I look in the Alexa app at my devices, I not only see my own, but also the devices of my nephew (because he uses the Prime acct for his devices), but I decide it was worth the slight annoyance of seeing his devices in my Alexa app to get all of the benefits of Both accounts on ONE Fire HD Tablet. Hope this helps someone. Your mileage may vary, as they say.

Cheers!