Does this do what you want (at least in this test case)
\definepagebreak [mychapterpagebreak] [yes,header,footer,right]
\setuphead [chapter] [page=mychapterpagebreak]
\setuppagenumbering[alternative=doublesided,location={header,margin}] \setupheadertexts[{My special headertext}] \setupfootertexts[This is a text in the footer]
\starttext \chapter {testA} \dorecurse{10}{\input tufte } \chapter {testB} \dorecurse{10}{\input tufte } \chapter {testC} \dorecurse{10}{\input tufte } \stoptext
I thought I tried that on my book and it didn't work. My actual situation is more complicated with declarations of front matter, depositing of \completecontent, etc. However, I have now done it with the test case expanded to mimic my real situation and it does seem to work. I'll try it in my real file (again?).