>ooops, wrong ....
>CPCURRENT() ... 1250
>CPCURRENT(1) .... 1250

>LOCAL c
>c=strconv(filetostr("app.ini"),6, 1251,1)
>alines(aR, c)
>...

****************
>the problem is the opposite direction: from the VFP textbox (fontcharset=204) to App.ini, so that when I open the app.ini with notepad, see the Cyrillic alphabet, in certain sections.

In that case, try

xx = rtrim(thisform.text1.Value)  && or for this example xx = strconv('CFE5F0E020CFE5F0E89E', 16)
yy = strconv(m.xx, 5, 1251, 1)
=strtofile(m.yy, 'd:\tmp\1.txt', 2)  &&  with BOM marker

I can open the file with notepad and it displays the chars Пера Перић