Did you hold down the shift key (in windows. In Mac I think it's the option key) and click "UPDATE" (not restore!) and navigate to the 4.2 beta you'd downloaded and saved on your computer?
I've updated multiple times to the betas and it's always worked fine. You can always restore to 3.2.2 without having saved your shsh since 3.2.2 is the current firmware.
I think that's the problem, I restored. Should've just updated it. NOW the problem is it's stuck in 4.2 as the latest firmware at that "can't restore because not signed into dev." or whatever it says. It's stuck in 4.2, thinking it's the latest firmware, so I can't go back now...