diff --git a/src/xrCore/xrstring.h b/src/xrCore/xrstring.h
index 9af60082098..6103f0efc9e 100644
--- a/src/xrCore/xrstring.h
+++ b/src/xrCore/xrstring.h
@@ -206,7 +206,7 @@ IC void xr_strlwr(shared_str& src)
         int i = 0;
         while(lp[i])
         {
-            lp[i] = (char) std::tolower(lp[i], std::locale());
+            lp[i] = (char) std::toupper(lp[i], std::locale());
             i++;
         }
 #endif
@@ -217,7 +217,13 @@ IC void xr_strlwr(shared_str& src)
 
 IC char * xr_strlwr(char * src)
 {
-    return SDL_strlwr(src);
+    int i = 0;
+    while(src[i])
+    {
+    	src[i] = (char) toupper(src[i]);// TODO rewrite locale-independent toupper_l()
+    	i++;
+    }
+    return src;
 }
 
 #pragma pack(pop)