diff --git a/src/lib/uri.cpp b/src/lib/uri.cpp
index 7780732..9cd24ef 100644
--- a/src/lib/uri.cpp
+++ b/src/lib/uri.cpp
@@ -688,6 +688,11 @@ string URI::to_utf8(const string &str)
         detect_encoding();
     }
 
+    if (_encoding == "utf-8")
+    {
+        return str;
+    }
+
     return boost::locale::conv::to_utf<char>(str, _encoding);
 }
 
@@ -698,7 +703,7 @@ void URI::detect_encoding()
     re_encoding.split(_document, matches);
     if (matches.size() >= 2)
     {
-        _encoding = matches[1];
+        _encoding = boost::locale::to_lower(matches[1]);
     }
 }