Force set UTF-8

I have a file with some debug data.
99% of this file is text and only in the beginning of the file are binary data. So when I set UTF-8 in the settings, there is no effect. Is there a way (or maybe feature request) to convert only selected part of text into UTF-8?
P.S. When I open this file in Far 3.0 editor, the text is shown correctly.