diff --git a/check.t b/check.t
index 8b6761f..42c1723 100644
--- a/check.t
+++ b/check.t
@@ -1,4 +1,4 @@
-# $MirOS: src/bin/mksh/check.t,v 1.440 2011/03/28 21:18:00 tg Exp $
+# $MirOS: src/bin/mksh/check.t,v 1.441 2011/03/28 21:30:59 tg Exp $
 # $OpenBSD: bksl-nl.t,v 1.2 2001/01/28 23:04:56 niklas Exp $
 # $OpenBSD: history.t,v 1.5 2001/01/28 23:04:56 niklas Exp $
 # $OpenBSD: read.t,v 1.3 2003/03/10 03:48:16 david Exp $
@@ -8664,8 +8664,7 @@ stdin:
 	pwd
 	cd ../lib
 	pwd
-	cd -P ../libexec
-	pwd
+	realpath //usr/include/../bin
 expected-stdout:
 	/bin
 	//bin
@@ -8677,8 +8676,8 @@ expected-stdout:
 	//bin
 	/bin
 	//usr/bin
-	//usr/bin/../lib
-	//usr/libexec
+	//usr/lib
+	//usr/bin
 ---
 name: crash-1
 description:
diff --git a/misc.c b/misc.c
index b2b3039..a26beab 100644
--- a/misc.c
+++ b/misc.c
@@ -29,7 +29,7 @@
 #include <grp.h>
 #endif
 
-__RCSID("$MirOS: src/bin/mksh/misc.c,v 1.163 2011/03/26 21:46:03 tg Exp $");
+__RCSID("$MirOS: src/bin/mksh/misc.c,v 1.164 2011/03/28 21:31:01 tg Exp $");
 
 /* type bits for unsigned char */
 unsigned char chtypes[UCHAR_MAX + 1];
@@ -1368,9 +1368,9 @@ do_realpath(const char *upath)
 				/* assert: (ip == ipath)[0] == '/' */
 				/* assert: xp == xs.beg => start of path */
 
-				/* exactly two leading slashes? */
+				/* exactly two leading slashes? (SUSv4 3.266) */
 				if (ip[1] == '/' && ip[2] != '/') {
-					/* SUSv4 3.266 Pathname */
+					/* keep them, e.g. for UNC pathnames */
 					Xput(xs, xp, '/');
 				}
 			}
@@ -1516,7 +1516,7 @@ make_path(const char *cwd, const char *file,
  *
  * simplify_path(this)			= that
  * /a/b/c/./../d/..			/a/b
- * //./C/foo/bar/../baz			//./C/foo/bar/../baz
+ * //./C/foo/bar/../baz			//C/foo/baz
  * /foo/				/foo
  * /foo/../../bar			/bar
  * /foo/./blah/..			/foo
@@ -1538,8 +1538,8 @@ simplify_path(char *p)
 	case '/':
 		/* exactly two leading slashes? (SUSv4 3.266) */
 		if (p[1] == '/' && p[2] != '/')
-			/* implementation defined, we CANNOT simplify this */
-			return;
+			/* keep them, e.g. for UNC pathnames */
+			++p;
 		needslash = true;
 		break;
 	default: