diff --git a/src/slic3r/GUI/fts_fuzzy_match.h b/src/slic3r/GUI/fts_fuzzy_match.h
index 34b2bbc5a..4dd206aac 100644
--- a/src/slic3r/GUI/fts_fuzzy_match.h
+++ b/src/slic3r/GUI/fts_fuzzy_match.h
@@ -116,10 +116,10 @@ namespace fts {
         	int  num_matched  = std::tolower(*pattern) == std::tolower(*str) ? 1 : 0;
         	bool folded_match = false;
         	if (! num_matched) {
-        		char tmp[4];
-        		char *end = Slic3r::fold_to_ascii(*str, tmp);
-        		char *c = tmp;
-                for (const wchar_t* d = pattern; c != end && *d != 0 && wchar_t(std::tolower(*c)) == std::tolower(*d); ++c, ++d);
+                wchar_t tmp[4];
+                wchar_t *end = Slic3r::fold_to_ascii(*str, tmp);
+                wchar_t *c = tmp;
+                for (const wchar_t* d = pattern; c != end && *d != 0 && std::towlower(*c) == std::towlower(*d); ++c, ++d);
                 if (c == end) {
         			folded_match = true;
         			num_matched = end - tmp;
diff --git a/src/slic3r/Utils/ASCIIFolding.cpp b/src/slic3r/Utils/ASCIIFolding.cpp
index fe70ef47f..4bd902c6d 100644
--- a/src/slic3r/Utils/ASCIIFolding.cpp
+++ b/src/slic3r/Utils/ASCIIFolding.cpp
@@ -11,7 +11,7 @@ namespace Slic3r {
 // Convert the input UNICODE character to a string of maximum 4 output ASCII characters.	
 // Return the end of the string written to the output.
 // The output buffer must be at least 4 characters long.
-char* fold_to_ascii(wchar_t c, char *out)
+wchar_t* fold_to_ascii(wchar_t c, wchar_t *out)
 {
 	if (c < 0x080) {
 	    *out ++ = c;
@@ -1925,7 +1925,7 @@ char* fold_to_ascii(wchar_t c, char *out)
 		    *out ++ = '~';
 		    break;
 		default:
-		    *out ++ = c;
+            *out ++ = c;
 		    break;
 		}
 	}
@@ -1934,6 +1934,14 @@ char* fold_to_ascii(wchar_t c, char *out)
 	return out;
 }
 
+static void fold_to_ascii(wchar_t c, std::back_insert_iterator<std::wstring>& out)
+{
+    wchar_t tmp[4];
+    wchar_t *end = fold_to_ascii(c, tmp);
+    for (wchar_t *it = tmp; it != end; ++ it)
+        *out = *it;
+}
+
 std::string fold_utf8_to_ascii(const std::string &src)
 {
 	std::wstring wstr = boost::locale::conv::utf_to_utf<wchar_t>(src.c_str(), src.c_str() + src.size());
@@ -1945,15 +1953,5 @@ std::string fold_utf8_to_ascii(const std::string &src)
 	return boost::locale::conv::utf_to_utf<char>(dst.c_str(), dst.c_str() + dst.size());
 }
 
-std::string fold_utf8_to_ascii(const char *src)
-{
-	std::wstring wstr = boost::locale::conv::utf_to_utf<wchar_t>(src, src + strlen(src));
-	std::wstring dst;
-	dst.reserve(wstr.size());
-	auto out = std::back_insert_iterator<std::wstring>(dst);
-	for (wchar_t c : wstr)
-		fold_to_ascii(c, out);
-	return boost::locale::conv::utf_to_utf<char>(dst.c_str(), dst.c_str() + dst.size());
-}
 
-}; // namespace Slic3r
+} // namespace Slic3r
diff --git a/src/slic3r/Utils/ASCIIFolding.hpp b/src/slic3r/Utils/ASCIIFolding.hpp
index d6ad491ab..0a4aff3da 100644
--- a/src/slic3r/Utils/ASCIIFolding.hpp
+++ b/src/slic3r/Utils/ASCIIFolding.hpp
@@ -7,23 +7,13 @@ namespace Slic3r {
 
 // If possible, remove accents from accented latin characters.
 // This function is useful for generating file names to be processed by legacy firmwares.
-extern std::string 	fold_utf8_to_ascii(const char *src);
 extern std::string 	fold_utf8_to_ascii(const std::string &src);
 
 // Convert the input UNICODE character to a string of maximum 4 output ASCII characters.
 // Return the end of the string written to the output.
 // The output buffer must be at least 4 characters long.
-extern char* 		fold_to_ascii(wchar_t c, char *out);
+extern wchar_t* fold_to_ascii(wchar_t c, wchar_t *out);
 
-template<typename OUTPUT_ITERATOR> 
-void fold_to_ascii(wchar_t c, OUTPUT_ITERATOR out)
-{
-	char tmp[4];
-	char *end = fold_to_ascii(c, tmp);
-	for (char *it = tmp; it != end; ++ it)
-		*out = *it;
-}
-
-}; // namespace Slic3r
+} // namespace Slic3r
 
 #endif /* slic3r_ASCIIFolding_hpp_ */