Document Classes ⇒ beamer remove TOC header

[CoolnessItself]

I'd like to remove the header (but keep the footer) for all slides, while keeping the actual TOC slide.

I've tried \setbeamertemplate{headline}[default] but this keeps a space for the header.
I've tried \begin{frame}[plain] \end{frame} but this removes the footer.

Suggestions?