Whilst it might not be what you want to hear, at some point you did click on a button to say "Update Automatically" otherwise the aTV4 wouldn't have automatically updated. I didn't, so had to go into the menu to update to the 10 beta, but even after running that, I selected not to update automatically so I can still choose which further beta releases I want to install.
From past experience, it's unwise to let any software, from any supplier, update automatically as you run the risk of functionality breaking, beta or not. Manually updating gives you the option to check out the websites and forums beforehand to check if other are having problems first.