> There was a special released to explain what happened to Jason.

An Annual, last year.

>According to that, he wasn't supposed to have died. It was one of the things that went wrong in the DCU that wasn't supposed to have happened.

Yup.

> So Superboy's punch restored him to life. I think as if he hadn't died.

Well, sort of. He was restored to the state he would have been in if he hadn't actually died, but had still been beaten and had the bomb go off. Essentially horribly injured. Geographically he was in the place his corpse had been, buried six feet under. And he was age he would have been if he hadn't died.

>Even if not, I don't think he was dead for very long before being restored.

The Annual was a bit vague about that,