Demo Mode can only be invoked on the first OOBE screen (welcome & network selection). But if the user follows the normal OOBE flow and accepts the EULA, they can't return to the Welcome screen without a powerwash (?).

We should enable the accelerator on post-EULA screens as well, in particular at the "Sign in" screen.

Alternatively we could provide a way to return to the Welcome screen, but there isn't a need for this apart from Demo Mode.