vertical alignment with multicolumn and multiline cell content

Question

I have a problem regarding the same file like described here: Centered cells with tabularx and linebreak Using that Code:

\documentclass{article}
\usepackage[utf8]{inputenc}
\usepackage{tabularx}
\usepackage[]{multirow}
\usepackage[]{MnSymbol}
\usepackage[]{array}
\usepackage{multicol}
\begin{document}
\maketitle
\section{Introduction}
\newcolumntype{P}[1]{>{\centering\arraybackslash}p{#1}}
\begin{table}
    \centering
    \begin{tabularx}{1\linewidth}{lX|P{0.2\linewidth}|P{0.2\linewidth}|P{0.2\linewidth}}
        & & \textbf{firmware} & \textbf{bootloader} & \textbf{os} \
        \multicolumn{2}{l}{\textbf{Target1}} &  &  &  \
        & {\footnotesize rot\par} & test123 \newline hallo &  {\footnotesize $(\uparrow)$ \newline testtext\par} &  {\footnotesize $(\nearrow)$ \newline hardware\par} \
        \hline
        \hline
    \end{tabularx}
\end{table}
\end{document}

Will result in

Is there anyway to align the first cell with in the mid of the other cells? Regardless if there are two, three, one or four lines in the cells?

Answer 1

Something like this below?

\documentclass{article}
\usepackage{array}
\usepackage{tabularx}
% \usepackage{multirow}
\usepackage{makecell}
\usepackage{MnSymbol}
\newcolumntype{P}[1]{>{\centering\arraybackslash}p{#1}}
\newcolumntype{C}{>{\centering\arraybackslash}X}
\begin{document}
\section{Introduction}
\begin{table}
    \renewcommand\theadfont{\normalsize\bfseries}%
    \setlength\tabcolsep{3pt}
    \centering%
    \footnotesize%
    \begin{tabularx}{\linewidth}{
            C|
            P{0.2\linewidth}|
            P{0.2\linewidth}|
            P{0.2\linewidth}
        }
        \thead{Target1}
            & \thead{firmware}
            & \thead{bootloader}
            & \thead{os} \
        rot
            & \makecell[cc]{$(\uparrow)$ test123\hallo}
            & $(\uparrow)$ testtext
            & $(\nearrow)$ hardware \
        \hline\hline
    \end{tabularx}
\end{table}
\end{document}