\setuppagenumbering[location=,alternative=doublesided]
%https://tex.stackexchange.com/questions/128854/context-eliminate-topspace-and-bottomspace?rq=1
\definelayer
[pagenumber]
[
width=\paperwidth,
height=\paperheight,
% preset=rightbottom,
voffset=.3\paperheight
]
%\setupbackgrounds[page][background=pagenumber, setups=setpagenumber]
\setupbackgrounds[text] [rightmargin] [background=pagenumber, setups=setpagenumber]
%isso aqui é o que funciona para doublesided (frente e verso)
\startsetups setpagenumber
% Set the page number to be (2em, \lineheight) from the bottom right corner
% Note the `preset=rightbottom` above.
%
% The 2nd set of optional arguments are for the frame. For illustration I change
% the color and font of the page number
\setlayerframed
[pagenumber]
[
x=3em,
y=2em,
]
[
frame=on,
foregroundcolor=red,
foregroundstyle=bold,
]
{\pagenumber}
\stopsetups
% Disable default page numbering
\starttext
Page 1
\page
Page 2
\page
Page 3
\page
Page 4
\dorecurse{15}{\input knuth}
\stoptext
=====================
Thanks a lot for any help!