1 files changed, 1 insertions, 0 deletions
diff --git a/io.c b/io.c
index 1833835cc9..88217efe0a 100644
--- a/io.c
+++ b/io.c
@@ -3500,6 +3500,7 @@ rb_io_binmode(VALUE io)
         rb_econv_binmode(fptr->writeconv);
     fptr->mode |= FMODE_BINMODE;
     fptr->mode &= ~FMODE_TEXTMODE;
+    fptr->writeconv_pre_ecflags &= ~(ECONV_UNIVERSAL_NEWLINE_DECODER|ECONV_CRLF_NEWLINE_ENCODER|ECONV_CR_NEWLINE_ENCODER);
     return io;
 }