diff --git a/bin/dd/dd.c b/bin/dd/dd.c
index 451715bc756d..60d7e677c1b1 100644
--- a/bin/dd/dd.c
+++ b/bin/dd/dd.c
@@ -34,7 +34,7 @@
  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  * SUCH DAMAGE.
  *
- *	$Id$
+ *	$Id: dd.c,v 1.10 1997/02/22 14:02:44 peter Exp $
  */
 
 #ifndef lint
@@ -236,19 +236,18 @@ getfdtype(io)
 static void
 dd_in()
 {
-	int flags, n;
+	int n;
 
-	for (flags = ddflags;;) {
+	for (;;) {
 		if (cpy_cnt && (st.in_full + st.in_part) >= cpy_cnt)
 			return;
 
 		/*
-		 * Zero the buffer first if trying to recover from errors so
-		 * lose the minimum amount of data.  If doing block operations
+		 * Zero the buffer first if sync; If doing block operations
 		 * use spaces.
 		 */
-		if ((flags & (C_NOERROR|C_SYNC)) == (C_NOERROR|C_SYNC))
-			if (flags & (C_BLOCK|C_UNBLOCK))
+		if (ddflags & C_SYNC)
+			if (ddflags & (C_BLOCK|C_UNBLOCK))
 				memset(in.dbp, ' ', in.dbsz);
 			else
 				memset(in.dbp, 0, in.dbsz);
@@ -265,7 +264,7 @@ dd_in()
 			 * If noerror not specified, die.  POSIX requires that
 			 * the warning message be followed by an I/O display.
 			 */
-			if (!(flags & C_NOERROR))
+			if (!(ddflags & C_NOERROR))
 				err(1, "%s", in.name);
 			warn("%s", in.name);
 			summary();
@@ -341,8 +340,11 @@ dd_close()
 		block_close();
 	else if (cfunc == unblock)
 		unblock_close();
-	if (ddflags & C_OSYNC && out.dbcnt < out.dbsz) {
-		memset(out.dbp, 0, out.dbsz - out.dbcnt);
+	if (ddflags & C_OSYNC && out.dbcnt && out.dbcnt < out.dbsz) {
+		if (ddflags & (C_BLOCK|C_UNBLOCK))
+			memset(out.dbp, ' ', out.dbsz - out.dbcnt);
+		else
+			memset(out.dbp, 0, out.dbsz - out.dbcnt);
 		out.dbcnt = out.dbsz;
 	}
 	if (out.dbcnt)