Yathesis : sous sections numérotées dans un chapitre non numéroté

\documentclass{yathesis}
\usepackage{chngcntr}

\begin{document}
\makeatletter
\renewcommandtwoopt{\YAD@starred@chapter}[3][][]{%
  \booltrue{YAD@nonnumbered@chapter}%
  \boolfalse{YAD@nonnumbered@section}%
  \boolfalse{YAD@nonnumbered@subsection}%
  \boolfalse{YAD@nonnumbered@subsubsection}%
  \boolfalse{YAD@nonnumbered@paragraph}%
  \boolfalse{YAD@nonnumbered@subparagraph}%
  \YAD@setsecnumdepth{\YAD@secnumdepth}%
  \YAD@tmp@chapter[#1][#2]{#3}%
}%
\makeatother

\chapter*{Test}

\counterwithout{section}{chapter}

\section{Test}

\mainmatter
\counterwithin{section}{chapter}

% on redéfinit la commande comme dans la classe
\makeatletter
  \renewcommandtwoopt{\YAD@starred@chapter}[3][][]{%
    \booltrue{YAD@nonnumbered@chapter}%
    \booltrue{YAD@nonnumbered@section}%
    \booltrue{YAD@nonnumbered@subsection}%
    \booltrue{YAD@nonnumbered@subsubsection}%
    \booltrue{YAD@nonnumbered@paragraph}%
    \booltrue{YAD@nonnumbered@subparagraph}%
    \YAD@setsecnumdepth{none}%
    \YAD@tmp@chapter[#1][#2]{#3}%
  }
\makeatother
\chapter{Test2}
\section{Quoi?}
\chapter{Test3}
\section{Et alors?}
\end{document}