diff --git a/sbin/gpt/Makefile b/sbin/gpt/Makefile
index 94a6b5606e79..8b9705d836ba 100644
--- a/sbin/gpt/Makefile
+++ b/sbin/gpt/Makefile
@@ -1,9 +1,9 @@
-# $NetBSD: Makefile,v 1.5 2013/11/20 08:08:47 jnemeth Exp $
+# $NetBSD: Makefile,v 1.6 2013/12/09 08:03:17 jnemeth Exp $
 # $FreeBSD: src/sbin/gpt/Makefile,v 1.7 2005/09/01 02:49:20 marcel Exp $
 
 PROG=	gpt
 SRCS=	add.c biosboot.c create.c destroy.c gpt.c label.c map.c migrate.c \
-	recover.c remove.c resize.c show.c
+	recover.c remove.c resize.c set.c show.c unset.c
 MAN=	gpt.8
 
 LDADD+=	-lprop -lutil
diff --git a/sbin/gpt/gpt.8 b/sbin/gpt/gpt.8
index 66a7278476f8..d19e8b986dbb 100644
--- a/sbin/gpt/gpt.8
+++ b/sbin/gpt/gpt.8
@@ -1,4 +1,4 @@
-.\" $NetBSD: gpt.8,v 1.24 2013/12/09 01:35:02 jnemeth Exp $
+.\" $NetBSD: gpt.8,v 1.25 2013/12/09 08:03:17 jnemeth Exp $
 .\"
 .\" Copyright (c) 2002 Marcel Moolenaar
 .\" All rights reserved.
@@ -26,7 +26,7 @@
 .\"
 .\" $FreeBSD: src/sbin/gpt/gpt.8,v 1.17 2006/06/22 22:22:32 marcel Exp $
 .\"
-.Dd December 8, 2013
+.Dd December 9, 2013
 .Dt GPT 8
 .Os
 .Sh NAME
@@ -344,6 +344,35 @@ If the
 .Fl a
 option is specified then the size will be adjusted to be a multiple of
 alignment if possible.
+.\" ==== set ====
+.It Nm Ic set Fl a Ar attribute Fl i Ar index Ar device ...
+The
+.Ic set
+command sets various partition attributes.
+The
+.Fl a
+option specifies which attributes to set and may be specified more then once.
+The
+.Fl i
+option specifies which entry to update.
+The possible attributes are
+.Do biosboot Dc ,
+.Do bootme Dc ,
+.Do bootonce Dc , and
+.Do bootfailed Dc .
+The biosboot flag is used to indicate which partition should be booted
+by legacy BIOS boot code.
+See the
+.Ic biosboot
+command for more information.
+The other three attributes are for compatibility with
+.Fx
+and are not currently used by any
+.Nx
+code.
+They may be used by
+.Nx
+code in the future.
 .\" ==== show ====
 .It Nm Ic show Oo Fl glu Oc Oo Fl i Ar index Oc Ar device ...
 The
@@ -372,6 +401,35 @@ The order of precedence for the options are:
 .Fl l ,
 .Fl g ,
 .Fl u .
+.\" ==== unset ====
+.It Nm Ic unset Fl a Ar attribute Fl i Ar index Ar device ...
+The
+.Ic unset
+command unsets various partition attributes.
+The
+.Fl a
+option specifies which attributes to unset and may be specified more then once.
+The
+.Fl i
+option specifies which entry to update.
+The possible attributes are
+.Do biosboot Dc ,
+.Do bootme Dc ,
+.Do bootonce Dc , and
+.Do bootfailed Dc .
+The biosboot flag is used to indicate which partition should be booted
+by legacy BIOS boot code.
+See the
+.Ic biosboot
+command for more information.
+The other three attributes are for compatibility with
+.Fx
+and are not currently used by any
+.Nx
+code.
+They may be used by
+.Nx
+code in the future.
 .El
 .Sh EXAMPLES
 .Bd -literal
diff --git a/sbin/gpt/gpt.c b/sbin/gpt/gpt.c
index 7a5cc0d5d8d1..acd021b624d3 100644
--- a/sbin/gpt/gpt.c
+++ b/sbin/gpt/gpt.c
@@ -31,7 +31,7 @@
 __FBSDID("$FreeBSD: src/sbin/gpt/gpt.c,v 1.16 2006/07/07 02:44:23 marcel Exp $");
 #endif
 #ifdef __RCSID
-__RCSID("$NetBSD: gpt.c,v 1.25 2013/12/04 20:15:51 jakllsch Exp $");
+__RCSID("$NetBSD: gpt.c,v 1.26 2013/12/09 08:03:17 jnemeth Exp $");
 #endif
 
 #include <sys/param.h>
@@ -727,7 +727,9 @@ static struct {
 	{ cmd_remove, "remove" },
 	{ NULL, "rename" },
 	{ cmd_resize, "resize" },
+	{ cmd_set, "set" },
 	{ cmd_show, "show" },
+	{ cmd_unset, "unset" },
 	{ NULL, "verify" },
 	{ NULL, NULL }
 };
@@ -738,7 +740,8 @@ usage(void)
 	extern const char addmsg1[], addmsg2[], biosbootmsg[], createmsg[];
 	extern const char destroymsg[], labelmsg1[], labelmsg2[], labelmsg3[];
 	extern const char migratemsg[], recovermsg[], removemsg1[];
-	extern const char removemsg2[], resizemsg[], showmsg[];
+	extern const char removemsg2[], resizemsg[], setmsg[], showmsg[];
+	extern const char unsetmsg[];
 
 	fprintf(stderr,
 	    "usage: %s %s\n"
@@ -754,6 +757,8 @@ usage(void)
 	    "       %s %s\n"
 	    "       %s %s\n"
 	    "       %s %s\n"
+	    "       %s %s\n"
+	    "       %s %s\n"
 	    "       %s %s\n",
 	    getprogname(), addmsg1,
 	    getprogname(), addmsg2,
@@ -768,7 +773,9 @@ usage(void)
 	    getprogname(), removemsg1,
 	    getprogname(), removemsg2,
 	    getprogname(), resizemsg,
-	    getprogname(), showmsg);
+	    getprogname(), setmsg,
+	    getprogname(), showmsg,
+	    getprogname(), unsetmsg);
 	exit(1);
 }
 
diff --git a/sbin/gpt/gpt.h b/sbin/gpt/gpt.h
index 2b081e6a72f8..295d1f170afb 100644
--- a/sbin/gpt/gpt.h
+++ b/sbin/gpt/gpt.h
@@ -88,6 +88,8 @@ int	cmd_migrate(int, char *[]);
 int	cmd_recover(int, char *[]);
 int	cmd_remove(int, char *[]);
 int	cmd_resize(int, char *[]);
+int	cmd_set(int, char *[]);
 int	cmd_show(int, char *[]);
+int	cmd_unset(int, char *[]);
 
 #endif /* _GPT_H_ */
diff --git a/sbin/gpt/set.c b/sbin/gpt/set.c
new file mode 100644
index 000000000000..1403c8a6740e
--- /dev/null
+++ b/sbin/gpt/set.c
@@ -0,0 +1,188 @@
+/*-
+ * Copyright (c) 2002 Marcel Moolenaar
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
+ * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
+ * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
+ * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
+ * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
+ * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
+ * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#include <sys/cdefs.h>
+#ifdef __FBSDID
+__FBSDID("$FreeBSD: src/sbin/gpt/add.c,v 1.14 2006/06/22 22:05:28 marcel Exp $");
+#endif
+#ifdef __RCSID
+__RCSID("$NetBSD: set.c,v 1.1 2013/12/09 08:03:17 jnemeth Exp $");
+#endif
+
+#include <sys/types.h>
+
+#include <err.h>
+#include <stddef.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+#include <inttypes.h>
+
+#include "map.h"
+#include "gpt.h"
+
+static unsigned int entry;
+static uint64_t attributes;
+
+const char setmsg[] = "set -a attribute -i index device ...";
+
+__dead static void
+usage_set(void)
+{
+
+	fprintf(stderr,
+	    "usage: %s %s\n", getprogname(), setmsg);
+	exit(1);
+}
+
+static void
+set(int fd)
+{
+	uuid_t uuid;
+	map_t *gpt, *tpg;
+	map_t *tbl, *lbt;
+	struct gpt_hdr *hdr;
+	struct gpt_ent *ent;
+	unsigned int i;
+	
+
+	gpt = map_find(MAP_TYPE_PRI_GPT_HDR);
+	ent = NULL;
+	if (gpt == NULL) {
+		warnx("%s: error: no primary GPT header; run create or recover",
+		    device_name);
+		return;
+	}
+
+	tpg = map_find(MAP_TYPE_SEC_GPT_HDR);
+	if (tpg == NULL) {
+		warnx("%s: error: no secondary GPT header; run recover",
+		    device_name);
+		return;
+	}
+
+	tbl = map_find(MAP_TYPE_PRI_GPT_TBL);
+	lbt = map_find(MAP_TYPE_SEC_GPT_TBL);
+	if (tbl == NULL || lbt == NULL) {
+		warnx("%s: error: run recover -- trust me", device_name);
+		return;
+	}
+
+	hdr = gpt->map_data;
+	if (entry > le32toh(hdr->hdr_entries)) {
+		warnx("%s: error: index %u out of range (%u max)", device_name,
+		    entry, le32toh(hdr->hdr_entries));
+		return;
+	}
+
+	i = entry - 1;
+	ent = (void*)((char*)tbl->map_data + i *
+	    le32toh(hdr->hdr_entsz));
+	le_uuid_dec(ent->ent_type, &uuid);
+	if (uuid_is_nil(&uuid, NULL)) {
+		warnx("%s: error: entry at index %u is unused",
+		    device_name, entry);
+		return;
+	}
+
+	ent->ent_attr |= attributes;
+
+	hdr->hdr_crc_table = htole32(crc32(tbl->map_data,
+	    le32toh(hdr->hdr_entries) * le32toh(hdr->hdr_entsz)));
+	hdr->hdr_crc_self = 0;
+	hdr->hdr_crc_self = htole32(crc32(hdr, le32toh(hdr->hdr_size)));
+
+	gpt_write(fd, gpt);
+	gpt_write(fd, tbl);
+
+	hdr = tpg->map_data;
+	ent = (void*)((char*)lbt->map_data + i * le32toh(hdr->hdr_entsz));
+	ent->ent_attr |= attributes;
+
+	hdr->hdr_crc_table = htole32(crc32(lbt->map_data,
+	    le32toh(hdr->hdr_entries) * le32toh(hdr->hdr_entsz)));
+	hdr->hdr_crc_self = 0;
+	hdr->hdr_crc_self = htole32(crc32(hdr, le32toh(hdr->hdr_size)));
+
+	gpt_write(fd, lbt);
+	gpt_write(fd, tpg);
+
+	printf("Partition attributes updated\n");
+}
+
+int
+cmd_set(int argc, char *argv[])
+{
+	char *p;
+	int ch, fd;
+
+	while ((ch = getopt(argc, argv, "a:i:")) != -1) {
+		switch(ch) {
+		case 'a':
+			if (strcmp(optarg, "biosboot") == 0)
+				attributes |= GPT_ENT_ATTR_LEGACY_BIOS_BOOTABLE;
+			else if (strcmp(optarg, "bootme") == 0)
+				attributes |= GPT_ENT_ATTR_BOOTME;
+			else if (strcmp(optarg, "bootonce") == 0)
+				attributes |= GPT_ENT_ATTR_BOOTONCE;
+			else if (strcmp(optarg, "bootfailed") == 0)
+				attributes |= GPT_ENT_ATTR_BOOTFAILED;
+			else
+				usage_set();
+			break;
+		case 'i':
+			if (entry > 0)
+				usage_set();
+			entry = strtoul(optarg, &p, 10);
+			if (*p != 0 || entry < 1)
+				usage_set();
+			break;
+		default:
+			usage_set();
+		}
+	}
+
+	if (argc == optind)
+		usage_set();
+
+	if (entry == 0 || attributes == 0)
+		usage_set();
+
+	while (optind < argc) {
+		fd = gpt_open(argv[optind++]);
+		if (fd == -1) {
+			warn("unable to open device '%s'", device_name);
+			continue;
+		}
+
+		set(fd);
+
+		gpt_close(fd);
+	}
+
+	return 0;
+}
diff --git a/sbin/gpt/unset.c b/sbin/gpt/unset.c
new file mode 100644
index 000000000000..e44f5b7f0002
--- /dev/null
+++ b/sbin/gpt/unset.c
@@ -0,0 +1,188 @@
+/*-
+ * Copyright (c) 2002 Marcel Moolenaar
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
+ * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
+ * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
+ * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
+ * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
+ * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
+ * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#include <sys/cdefs.h>
+#ifdef __FBSDID
+__FBSDID("$FreeBSD: src/sbin/gpt/add.c,v 1.14 2006/06/22 22:05:28 marcel Exp $");
+#endif
+#ifdef __RCSID
+__RCSID("$NetBSD: unset.c,v 1.1 2013/12/09 08:03:17 jnemeth Exp $");
+#endif
+
+#include <sys/types.h>
+
+#include <err.h>
+#include <stddef.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+#include <inttypes.h>
+
+#include "map.h"
+#include "gpt.h"
+
+static unsigned int entry;
+static uint64_t attributes;
+
+const char unsetmsg[] = "unset -a attribute -i index device ...";
+
+__dead static void
+usage_unset(void)
+{
+
+	fprintf(stderr,
+	    "usage: %s %s\n", getprogname(), unsetmsg);
+	exit(1);
+}
+
+static void
+unset(int fd)
+{
+	uuid_t uuid;
+	map_t *gpt, *tpg;
+	map_t *tbl, *lbt;
+	struct gpt_hdr *hdr;
+	struct gpt_ent *ent;
+	unsigned int i;
+	
+
+	gpt = map_find(MAP_TYPE_PRI_GPT_HDR);
+	ent = NULL;
+	if (gpt == NULL) {
+		warnx("%s: error: no primary GPT header; run create or recover",
+		    device_name);
+		return;
+	}
+
+	tpg = map_find(MAP_TYPE_SEC_GPT_HDR);
+	if (tpg == NULL) {
+		warnx("%s: error: no secondary GPT header; run recover",
+		    device_name);
+		return;
+	}
+
+	tbl = map_find(MAP_TYPE_PRI_GPT_TBL);
+	lbt = map_find(MAP_TYPE_SEC_GPT_TBL);
+	if (tbl == NULL || lbt == NULL) {
+		warnx("%s: error: run recover -- trust me", device_name);
+		return;
+	}
+
+	hdr = gpt->map_data;
+	if (entry > le32toh(hdr->hdr_entries)) {
+		warnx("%s: error: index %u out of range (%u max)", device_name,
+		    entry, le32toh(hdr->hdr_entries));
+		return;
+	}
+
+	i = entry - 1;
+	ent = (void*)((char*)tbl->map_data + i *
+	    le32toh(hdr->hdr_entsz));
+	le_uuid_dec(ent->ent_type, &uuid);
+	if (uuid_is_nil(&uuid, NULL)) {
+		warnx("%s: error: entry at index %u is unused",
+		    device_name, entry);
+		return;
+	}
+
+	ent->ent_attr &= ~attributes;
+
+	hdr->hdr_crc_table = htole32(crc32(tbl->map_data,
+	    le32toh(hdr->hdr_entries) * le32toh(hdr->hdr_entsz)));
+	hdr->hdr_crc_self = 0;
+	hdr->hdr_crc_self = htole32(crc32(hdr, le32toh(hdr->hdr_size)));
+
+	gpt_write(fd, gpt);
+	gpt_write(fd, tbl);
+
+	hdr = tpg->map_data;
+	ent = (void*)((char*)lbt->map_data + i * le32toh(hdr->hdr_entsz));
+	ent->ent_attr &= ~attributes;
+
+	hdr->hdr_crc_table = htole32(crc32(lbt->map_data,
+	    le32toh(hdr->hdr_entries) * le32toh(hdr->hdr_entsz)));
+	hdr->hdr_crc_self = 0;
+	hdr->hdr_crc_self = htole32(crc32(hdr, le32toh(hdr->hdr_size)));
+
+	gpt_write(fd, lbt);
+	gpt_write(fd, tpg);
+
+	printf("Partition attributes updated\n");
+}
+
+int
+cmd_unset(int argc, char *argv[])
+{
+	char *p;
+	int ch, fd;
+
+	while ((ch = getopt(argc, argv, "a:i:")) != -1) {
+		switch(ch) {
+		case 'a':
+			if (strcmp(optarg, "biosboot") == 0)
+				attributes |= GPT_ENT_ATTR_LEGACY_BIOS_BOOTABLE;
+			else if (strcmp(optarg, "bootme") == 0)
+				attributes |= GPT_ENT_ATTR_BOOTME;
+			else if (strcmp(optarg, "bootonce") == 0)
+				attributes |= GPT_ENT_ATTR_BOOTONCE;
+			else if (strcmp(optarg, "bootfailed") == 0)
+				attributes |= GPT_ENT_ATTR_BOOTFAILED;
+			else
+				usage_unset();
+			break;
+		case 'i':
+			if (entry > 0)
+				usage_unset();
+			entry = strtoul(optarg, &p, 10);
+			if (*p != 0 || entry < 1)
+				usage_unset();
+			break;
+		default:
+			usage_unset();
+		}
+	}
+
+	if (argc == optind)
+		usage_unset();
+
+	if (entry == 0 || attributes == 0)
+		usage_unset();
+
+	while (optind < argc) {
+		fd = gpt_open(argv[optind++]);
+		if (fd == -1) {
+			warn("unable to open device '%s'", device_name);
+			continue;
+		}
+
+		unset(fd);
+
+		gpt_close(fd);
+	}
+
+	return 0;
+}