In TeX Live we treat all output files as binary.

diff -ur t1utils-1.41.orig/t1ascii.c t1utils-1.41/t1ascii.c
--- t1utils-1.41.orig/t1ascii.c	Thu Aug 17 01:31:02 2017
+++ t1utils-1.41/t1ascii.c	Mon Aug 28 15:43:58 2017
@@ -286,6 +286,7 @@
   /* As we are processing a PFB (binary) input */
   /* file, we must set its file mode to binary. */
   _setmode(_fileno(ifp), _O_BINARY);
+  _setmode(_fileno(ofp), _O_BINARY);
 #endif
 
   /* prepare font reader */
diff -ur t1utils-1.41.orig/t1asm.c t1utils-1.41/t1asm.c
--- t1utils-1.41.orig/t1asm.c	Thu Aug 17 01:31:11 2017
+++ t1utils-1.41/t1asm.c	Wed Aug 30 16:13:00 2017
@@ -715,8 +715,7 @@
 #if defined(_MSDOS) || defined(_WIN32)
   /* If we are processing a PFB (binary) output */
   /* file, we must set its file mode to binary. */
-  if (pfb)
-    _setmode(_fileno(ofp), _O_BINARY);
+  _setmode(_fileno(ofp), _O_BINARY);
 #endif
 
   /* Finally, we loop until no more input. Some special things to look for are
diff -ur t1utils-1.41.orig/t1disasm.c t1utils-1.41/t1disasm.c
--- t1utils-1.41.orig/t1disasm.c	Thu Aug 17 01:31:24 2017
+++ t1utils-1.41/t1disasm.c	Mon Aug 28 15:43:58 2017
@@ -727,6 +727,7 @@
   /* As we might be processing a PFB (binary) input file, we must set its file
      mode to binary. */
   _setmode(_fileno(ifp), _O_BINARY);
+  _setmode(_fileno(ofp), _O_BINARY);
 #endif
 
   /* prepare font reader */
diff -ur t1utils-1.41.orig/t1unmac.c t1utils-1.41/t1unmac.c
--- t1utils-1.41.orig/t1unmac.c	Thu Aug 17 01:31:39 2017
+++ t1utils-1.41/t1unmac.c	Mon Aug 28 15:43:58 2017
@@ -656,8 +655,7 @@
   _setmode(_fileno(ifp), _O_BINARY);
   /* If we are processing a PFB (binary) output */
   /* file, we must set its file mode to binary. */
-  if (pfb)
-    _setmode(_fileno(ofp), _O_BINARY);
+  _setmode(_fileno(ofp), _O_BINARY);
 #endif
 
   if (pfb)