Try this:
find . -type f -print -exec iconv -f iso8859-2 -t utf-8 -o {}.converted {} ; -exec mv {}.converted {} ;
It will use temp file with '.converted' suffix (extension) and then will move it to original name, so be careful if you have files with '.converted' suffixes (I don't think you have).
Also this script is not safe for filenames containing spaces, so for more safety you should double-quote: "{}" instead of {} and "{}.converted" instead of {}.converted
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