I have reason to believe the Nook Tablet is efuse locked. This means that we can only boot signed bootloaders from microSD.
I don't have the technical expertise to check his work, but right now I'm hoping that he's wrong. Because if he's right then it looks like Barnes & Noble made hacking the Nook Tablet incredibly difficult.
If you follow Android phone news then you've probably heard the term "signed bootloaders" before. This is a form of DRM that some hardware developers use to control what gets installed on their devices. (BTW, the Nook Color didn't have one, I don't think.)
This won't necessarily make it impossible to hack the Nook Tablet, but it does lower the chance of success and it adds another layer of work for the hackers. But I can recall at least one time that hackers have successfully overcome the DRM, so it's clearly not impossible.
But will anyone make the effort? Right now hackers have a choice of Android tablets to work on. We might see interest in the Nook Tablet dry up simply because there are other projects worth doing that aren't as hindered as the Nook Tablet.
And if the Nook Tablet isn't hacked (while the Kindle Fire is), then I'm not sure that the NT will be the better value anymore.