diff -rupN mksh491/mksh/exec.c mksh491_fix1a/mksh/exec.c
--- mksh491/mksh/exec.c	2014-01-12 03:26:52.000000000 +1100
+++ mksh491_fix1a/mksh/exec.c	2014-12-05 10:18:53.362891300 +1100
@@ -865,7 +865,7 @@ scriptexec(struct op *tp, const char **a
 	*tp->args-- = tp->str;
 
 #ifndef MKSH_SMALL
-	if ((fd = open(tp->str, O_RDONLY | O_BINARY)) >= 0) {
+	if ((fd = open(tp->str, O_RDONLY)) >= 0) {
 		/* read first MAXINTERP octets from file */
 		if (read(fd, buf, sizeof(buf)) <= 0)
 			/* read error -> no good */
@@ -1370,7 +1370,7 @@ iosetup(struct ioword *iop, struct tbl *
 			warningf(true, "%s: %s", cp, "restricted");
 			return (-1);
 		}
-		u = open(cp, flags | O_BINARY, 0666);
+		u = open(cp, flags, 0666);
 	}
 	if (u < 0) {
 		/* herein() may already have printed message */
@@ -1503,7 +1503,7 @@ herein(struct ioword *iop, char **resbuf
 	 * so temp doesn't get removed too soon).
 	 */
 	h = maketemp(ATEMP, TT_HEREDOC_EXP, &e->temps);
-	if (!(shf = h->shf) || (fd = open(h->tffn, O_RDONLY | O_BINARY, 0)) < 0) {
+	if (!(shf = h->shf) || (fd = open(h->tffn, O_RDONLY, 0)) < 0) {
 		i = errno;
 		warningf(true, "can't %s temporary file %s: %s",
 		    !shf ? "create" : "open", h->tffn, cstrerror(i));
diff -rupN mksh491/mksh/funcs.c mksh491_fix1a/mksh/funcs.c
--- mksh491/mksh/funcs.c	2014-01-06 06:20:56.000000000 +1100
+++ mksh491_fix1a/mksh/funcs.c	2014-12-05 10:18:22.433122200 +1100
@@ -3610,7 +3610,7 @@ c_cat(const char **wp)
 			fn = *wp++;
 			if (fn[0] == '-' && fn[1] == '\0')
 				fd = STDIN_FILENO;
-			else if ((fd = open(fn, O_RDONLY | O_BINARY)) < 0) {
+			else if ((fd = open(fn, O_RDONLY)) < 0) {
 				eno = errno;
 				bi_errorf("%s: %s", fn, cstrerror(eno));
 				rv = 1;
diff -rupN mksh491/mksh/histrap.c mksh491_fix1a/mksh/histrap.c
--- mksh491/mksh/histrap.c	2013-10-09 22:59:53.000000000 +1100
+++ mksh491_fix1a/mksh/histrap.c	2014-12-05 10:19:38.243458300 +1100
@@ -720,8 +720,7 @@ hist_init(Source *s)
 
  retry:
 	/* we have a file and are interactive */
-	if ((fd = open(hname, O_RDWR | O_CREAT | O_APPEND | O_BINARY,
-	    0600)) < 0)
+	if ((fd = open(hname, O_RDWR | O_CREAT | O_APPEND, 0600)) < 0)
 		return;
 
 	histfd = savefd(fd);
@@ -757,7 +756,7 @@ hist_init(Source *s)
 			/* create temporary file */
 			nhname = shf_smprintf("%s.%d", hname, (int)procpid);
 			if ((fd = open(nhname, O_RDWR | O_CREAT | O_TRUNC |
-			    O_EXCL | O_BINARY, 0600)) < 0) {
+			    O_EXCL, 0600)) < 0) {
 				/* just don't truncate then, meh. */
 				goto hist_trunc_dont;
 			}
diff -rupN mksh491/mksh/main.c mksh491_fix1a/mksh/main.c
--- mksh491/mksh/main.c	2014-01-12 05:10:05.000000000 +1100
+++ mksh491_fix1a/mksh/main.c	2014-12-05 10:20:05.658026300 +1100
@@ -1644,8 +1644,7 @@ maketemp(Area *ap, Temp_type type, struc
 	} while (len < 5);
 
 	/* cyclically attempt to open a temporary file */
-	while ((i = open(tp->tffn, O_CREAT | O_EXCL | O_RDWR | O_BINARY,
-	    0600)) < 0) {
+	while ((i = open(tp->tffn, O_CREAT | O_EXCL | O_RDWR, 0600)) < 0) {
 		if (errno != EEXIST)
 			goto maketemp_out;
 		/* count down from z to a then from 9 to 0 */
diff -rupN mksh491/mksh/misc.c mksh491_fix1a/mksh/misc.c
--- mksh491/mksh/misc.c	2014-01-06 08:57:52.000000000 +1100
+++ mksh491_fix1a/mksh/misc.c	2014-12-05 10:20:35.048707400 +1100
@@ -1996,9 +1996,9 @@ chvt(const Getopt *go)
 #endif
 	    }
 	}
-	if ((fd = open(dv, O_RDWR | O_BINARY)) < 0) {
+	if ((fd = open(dv, O_RDWR)) < 0) {
 		sleep(1);
-		if ((fd = open(dv, O_RDWR | O_BINARY)) < 0) {
+		if ((fd = open(dv, O_RDWR)) < 0) {
 			errorf("%s: %s %s", "chvt", "can't open", dv);
 		}
 	}
diff -rupN mksh491/mksh/shf.c mksh491_fix1a/mksh/shf.c
--- mksh491/mksh/shf.c	2013-10-09 22:59:55.000000000 +1100
+++ mksh491_fix1a/mksh/shf.c	2014-12-05 10:21:11.628799600 +1100
@@ -62,7 +62,7 @@ shf_open(const char *name, int oflags, i
 	shf->flags = SHF_ALLOCS;
 	/* Rest filled in by reopen. */
 
-	fd = open(name, oflags | O_BINARY, mode);
+	fd = open(name, oflags, mode);
 	if (fd < 0) {
 		eno = errno;
 		afree(shf, shf->areap);