Directv unfortunately does not have support yet for HBO Go on any Android devices besides Android phones. While we they are working on the software, it has not been released, nor is their a firm release date. Some customers have been able to work, but there is no official support for it.
The only tablets that are supported at this time are the Ipad and Kindle Fire. Android phones are supported fully, with the exception of these devices; Motorola: Flipout, CLIQ XT, Droid, CLIQ, Backflip, LG Ally, HTC: MyTouch 3G, Droid Eris, Hero, T-Mobile G1.
One thing to keep in mind is that DirecTV does not offer support for Jailbroken Apple devices or Rooted Android phones, if rooting was an option you wanted to try.
Perhaps another use could help with downgrading your OS to the previous version, I have never had to do that, and here at work I will not be able to utilize Google to help you out much there!