Preventing `mainmatter` from inserting a blank page

mainmatter seems to sometimes force a blank page if the current contents (the place where mainmatter is called) are on an odd numbered page. openany and oneside do not seem to work here. They only work when opening a new chapter, but not when the main matter starts.

I want to disable inserting of blank pages altogether even at the beginning of the main matter.

documentclass[11pt, openany, oneside]{book}

    usepackage[a4paper]{geometry}
% BEGIN_FOLD

    geometry{twoside=false, showframe=false,inner=1.05in,outer=1.05in,includemp=true,asymmetric=true,bindingoffset=0mm,marginparsep=0mm, marginparwidth=0mm}
    geometry{bottom=0.9in,vmarginratio=3:5,includehead=true, includefoot=true,headheight=8pt, headsep=14pt,footskip=10.9mm}

% END_FOLD

    usepackage{blindtext}

begin{document}

blindtext

tableofcontents
clearpage
blindtext

mainmatter
Blinddocument

end{document}

documentclass[11pt, openany, oneside]{book}

    usepackage[a4paper]{geometry}
% BEGIN_FOLD

    geometry{twoside=false, showframe=false,inner=1.05in,outer=1.05in,includemp=true,asymmetric=true,bindingoffset=0mm,marginparsep=0mm, marginparwidth=0mm}
    geometry{bottom=0.9in,vmarginratio=3:5,includehead=true, includefoot=true,headheight=8pt, headsep=14pt,footskip=10.9mm}

% END_FOLD

    usepackage{blindtext}

begin{document}

blindtext

tableofcontents
clearpage
blindtext

{
renewcommand{cleardoublepage}{newpage}
mainmatter
}
Blinddocument

end{document}