diff --git a/ChangeLog b/ChangeLog
index 14298013c5..20cc4c658f 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,4 +1,7 @@
-Fri May 27 22:38:54 2011  Nobuyoshi Nakada  <nobu@ruby-lang.org>
+Fri May 27 22:45:10 2011  Nobuyoshi Nakada  <nobu@ruby-lang.org>
+
+	* io.c (validate_enc_binmode): do not clear textmode flag if
+	  default.  fixed #4732
 
 	* io.c (fill_cbuf): finish reading at EOF.
 
diff --git a/io.c b/io.c
index 00f4ea62fa..bf06eaaecb 100644
--- a/io.c
+++ b/io.c
@@ -4419,10 +4419,12 @@ validate_enc_binmode(int *fmode_p, int ecflags, rb_encoding *enc, rb_encoding *e
 	fmode |= DEFAULT_TEXTMODE;
 	*fmode_p = fmode;
     }
+#if !DEFAULT_TEXTMODE
     else if (!(ecflags & ECONV_NEWLINE_DECORATOR_MASK)) {
 	fmode &= ~FMODE_TEXTMODE;
 	*fmode_p = fmode;
     }
+#endif
 }
 
 static void