Index: stand/efi/loader/main.c
===================================================================
--- stand/efi/loader/main.c
+++ stand/efi/loader/main.c
@@ -267,7 +267,7 @@
 	currdev.root_guid = 0;
 	set_currdev_devdesc((struct devdesc *)&currdev);
 	devname = efi_fmtdev(&currdev);
-	init_zfs_bootenv(devname);
+	init_zfs_boot_options(devname);
 
 	return (sanity_check_currdev());
 }
Index: stand/i386/loader/main.c
===================================================================
--- stand/i386/loader/main.c
+++ stand/i386/loader/main.c
@@ -342,7 +342,7 @@
 
 #ifdef LOADER_ZFS_SUPPORT
     if (new_currdev.dd.d_dev->dv_type == DEVT_ZFS)
-	init_zfs_bootenv(zfs_fmtdev(&new_currdev));
+	init_zfs_boot_options(zfs_fmtdev(&new_currdev));
 #endif
 
     env_setenv("currdev", EV_VOLATILE, i386_fmtdev(&new_currdev),
Index: stand/libsa/zfs/libzfs.h
===================================================================
--- stand/libsa/zfs/libzfs.h
+++ stand/libsa/zfs/libzfs.h
@@ -50,7 +50,7 @@
 int	zfs_probe_dev(const char *devname, uint64_t *pool_guid);
 int	zfs_list(const char *name);
 uint64_t ldi_get_size(void *);
-void	init_zfs_bootenv(const char *currdev);
+void	init_zfs_boot_options(const char *currdev);
 int	zfs_bootenv(const char *name);
 int	zfs_belist_add(const char *name, uint64_t __unused);
 int	zfs_set_env(void);
Index: stand/libsa/zfs/zfs.c
===================================================================
--- stand/libsa/zfs/zfs.c
+++ stand/libsa/zfs/zfs.c
@@ -60,7 +60,10 @@
 static int	zfs_stat(struct open_file *f, struct stat *sb);
 static int	zfs_readdir(struct open_file *f, struct dirent *d);
 
-static void	zfs_bootenv_initial(const char *);
+static void	zfs_bootenv_initial(const char *envname, spa_t *spa,
+		    const char *name, const char *dsname, int checkpoint);
+static void	zfs_checkpoints_initial(spa_t *spa, const char *name,
+		    const char *dsname);
 
 struct devsw zfs_dev;
 
@@ -817,15 +820,15 @@
 	return (buf);
 }
 
-int
-zfs_list(const char *name)
+static int
+split_devname(const char *name, char *poolname, size_t size,
+    const char **dsnamep)
 {
-	static char	poolname[ZFS_MAXNAMELEN];
-	uint64_t	objid;
-	spa_t		*spa;
-	const char	*dsname;
-	int		len;
-	int		rv;
+	const char *dsname;
+	size_t len;
+
+	ASSERT(name != NULL);
+	ASSERT(poolname != NULL);
 
 	len = strlen(name);
 	dsname = strchr(name, '/');
@@ -834,8 +837,29 @@
 		dsname++;
 	} else
 		dsname = "";
-	memcpy(poolname, name, len);
-	poolname[len] = '\0';
+
+	if (len + 1 > size)
+		return (EINVAL);
+
+	strlcpy(poolname, name, len + 1);
+
+	if (dsnamep != NULL)
+		*dsnamep = dsname;
+
+	return (0);
+}
+
+int
+zfs_list(const char *name)
+{
+	static char	poolname[ZFS_MAXNAMELEN];
+	uint64_t	objid;
+	spa_t		*spa;
+	const char	*dsname;
+	int		rv;
+
+	if (split_devname(name, poolname, sizeof(poolname), &dsname) != 0)
+		return (EINVAL);
 
 	spa = spa_find_by_name(poolname);
 	if (!spa)
@@ -848,10 +872,13 @@
 }
 
 void
-init_zfs_bootenv(const char *currdev_in)
+init_zfs_boot_options(const char *currdev_in)
 {
+	char poolname[ZFS_MAXNAMELEN];
 	char *beroot, *currdev;
+	spa_t *spa;
 	int currdev_len;
+	const char *dsname;
 
 	currdev = NULL;
 	currdev_len = strlen(currdev_in);
@@ -864,6 +891,7 @@
 		return;
 	/* Remove the trailing : */
 	currdev[currdev_len - 1] = '\0';
+
 	setenv("zfs_be_active", currdev, 1);
 	setenv("zfs_be_currpage", "1", 1);
 	/* Remove the last element (current bootenv) */
@@ -872,49 +900,71 @@
 		beroot[0] = '\0';
 	beroot = strchr(currdev, ':') + 1;
 	setenv("zfs_be_root", beroot, 1);
-	zfs_bootenv_initial(beroot);
+
+	if (split_devname(beroot, poolname, sizeof(poolname), &dsname) != 0)
+		return;
+
+	spa = spa_find_by_name(poolname);
+	if (spa == NULL)
+		return;
+
+	zfs_bootenv_initial("bootenvs", spa, beroot, dsname, 0);
+	zfs_checkpoints_initial(spa, beroot, dsname);
+
 	free(currdev);
 }
 
 static void
-zfs_bootenv_initial(const char *name)
+zfs_checkpoints_initial(spa_t *spa, const char *name, const char *dsname)
 {
-	char		poolname[ZFS_MAXNAMELEN], *dsname;
-	char envname[32], envval[256];
+	char envname[32];
+
+	if (spa->spa_uberblock_checkpoint.ub_checkpoint_txg != 0) {
+		snprintf(envname, sizeof(envname), "zpool_checkpoint");
+		setenv(envname, name, 1);
+
+		spa->spa_uberblock = &spa->spa_uberblock_checkpoint;
+		spa->spa_mos = &spa->spa_mos_checkpoint;
+
+		zfs_bootenv_initial("bootenvs_check", spa, name, dsname, 1);
+
+		spa->spa_uberblock = &spa->spa_uberblock_master;
+		spa->spa_mos = &spa->spa_mos_master;
+	}
+}
+
+static void
+zfs_bootenv_initial(const char *envprefix, spa_t *spa, const char *rootname,
+   const char *dsname, int checkpoint)
+{
+	char		envname[32], envval[256];
 	uint64_t	objid;
-	spa_t		*spa;
-	int		bootenvs_idx, len, rv;
+	int		bootenvs_idx, rv;
 
 	SLIST_INIT(&zfs_be_head);
 	zfs_env_count = 0;
-	len = strlen(name);
-	dsname = strchr(name, '/');
-	if (dsname != NULL) {
-		len = dsname - name;
-		dsname++;
-	} else
-		dsname = "";
-	strlcpy(poolname, name, len + 1);
-	spa = spa_find_by_name(poolname);
-	if (spa == NULL)
-		return;
+
 	rv = zfs_lookup_dataset(spa, dsname, &objid);
 	if (rv != 0)
 		return;
+
 	rv = zfs_callback_dataset(spa, objid, zfs_belist_add);
 	bootenvs_idx = 0;
 	/* Populate the initial environment variables */
 	SLIST_FOREACH_SAFE(zfs_be, &zfs_be_head, entries, zfs_be_tmp) {
 		/* Enumerate all bootenvs for general usage */
-		snprintf(envname, sizeof(envname), "bootenvs[%d]", bootenvs_idx);
-		snprintf(envval, sizeof(envval), "zfs:%s/%s", name, zfs_be->name);
+		snprintf(envname, sizeof(envname), "%s[%d]",
+		    envprefix, bootenvs_idx);
+		snprintf(envval, sizeof(envval), "zfs:%s%s/%s",
+		    checkpoint ? "!" : "", rootname, zfs_be->name);
 		rv = setenv(envname, envval, 1);
 		if (rv != 0)
 			break;
 		bootenvs_idx++;
 	}
+	snprintf(envname, sizeof(envname), "%s_count", envprefix);
 	snprintf(envval, sizeof(envval), "%d", bootenvs_idx);
-	setenv("bootenvs_count", envval, 1);
+	setenv(envname, envval, 1);
 
 	/* Clean up the SLIST of ZFS BEs */
 	while (!SLIST_EMPTY(&zfs_be_head)) {
@@ -923,19 +973,17 @@
 		free(zfs_be->name);
 		free(zfs_be);
 	}
-
-	return;
-
 }
 
 int
 zfs_bootenv(const char *name)
 {
-	static char	poolname[ZFS_MAXNAMELEN], *dsname, *root;
+	char		poolname[ZFS_MAXNAMELEN], *root;
+	const char	*dsname;
 	char		becount[4];
 	uint64_t	objid;
 	spa_t		*spa;
-	int		len, rv, pages, perpage, currpage;
+	int		rv, pages, perpage, currpage;
 
 	if (name == NULL)
 		return (EINVAL);
@@ -949,15 +997,9 @@
 
 	SLIST_INIT(&zfs_be_head);
 	zfs_env_count = 0;
-	len = strlen(name);
-	dsname = strchr(name, '/');
-	if (dsname != NULL) {
-		len = dsname - name;
-		dsname++;
-	} else
-		dsname = "";
-	memcpy(poolname, name, len);
-	poolname[len] = '\0';
+
+	if (split_devname(name, poolname, sizeof(poolname), &dsname) != 0)
+		return (EINVAL);
 
 	spa = spa_find_by_name(poolname);
 	if (!spa)
@@ -1047,7 +1089,7 @@
 			ctr++;
 			continue;
 		}
-		
+
 		snprintf(envname, sizeof(envname), "bootenvmenu_caption[%d]", zfs_env_index);
 		snprintf(envval, sizeof(envval), "%s", zfs_be->name);
 		rv = setenv(envname, envval, 1);
@@ -1080,7 +1122,7 @@
 		}
 
 	}
-	
+
 	for (; zfs_env_index <= ZFS_BE_LAST; zfs_env_index++) {
 		snprintf(envname, sizeof(envname), "bootenvmenu_caption[%d]", zfs_env_index);
 		(void)unsetenv(envname);
Index: stand/libsa/zfs/zfsimpl.c
===================================================================
--- stand/libsa/zfs/zfsimpl.c
+++ stand/libsa/zfs/zfsimpl.c
@@ -933,7 +933,7 @@
 
 		vic = &vdev->vdev_indirect_config;
 		vdev->v_mapping = vdev_indirect_mapping_open(spa,
-		    &spa->spa_mos, vic->vic_mapping_object);
+		    spa->spa_mos, vic->vic_mapping_object);
 	}
 
 	vdev_indirect_remap(vdev, offset, bytes, &zio);
@@ -1569,6 +1569,8 @@
 		free(spa);
 		return (NULL);
 	}
+	spa->spa_uberblock = &spa->spa_uberblock_master;
+	spa->spa_mos = &spa->spa_mos_master;
 	spa->spa_guid = guid;
 	spa->spa_root_vdev = vdev_create(guid, NULL);
 	if (spa->spa_root_vdev == NULL) {
@@ -2048,7 +2050,7 @@
 	 * the best uberblock and then we can actually access
 	 * the contents of the pool.
 	 */
-	vdev_uberblock_load(vdev, &spa->spa_uberblock);
+	vdev_uberblock_load(vdev, spa->spa_uberblock);
 
 	if (spap != NULL)
 		*spap = spa;
@@ -2572,8 +2574,9 @@
 	if (zh->zap_magic != ZAP_MAGIC)
 		return (EIO);
 
-	if ((rc = fzap_check_size(integer_size, num_integers)) != 0)
+	if ((rc = fzap_check_size(integer_size, num_integers)) != 0) {
 		return (rc);
+	}
 
 	z.zap_block_shift = ilog2(bsize);
 	z.zap_phys = zh;
@@ -2929,7 +2932,7 @@
 	p = &name[sizeof(name) - 1];
 	*p = '\0';
 
-	if (objset_get_dnode(spa, &spa->spa_mos, objnum, &dataset)) {
+	if (objset_get_dnode(spa, spa->spa_mos, objnum, &dataset)) {
 		printf("ZFS: can't find dataset %ju\n", (uintmax_t)objnum);
 		return (EIO);
 	}
@@ -2937,7 +2940,7 @@
 	dir_obj = ds->ds_dir_obj;
 
 	for (;;) {
-		if (objset_get_dnode(spa, &spa->spa_mos, dir_obj, &dir) != 0)
+		if (objset_get_dnode(spa, spa->spa_mos, dir_obj, &dir) != 0)
 			return (EIO);
 		dd = (dsl_dir_phys_t *)&dir.dn_bonus;
 
@@ -2946,12 +2949,12 @@
 		if (parent_obj == 0)
 			break;
 
-		if (objset_get_dnode(spa, &spa->spa_mos, parent_obj,
+		if (objset_get_dnode(spa, spa->spa_mos, parent_obj,
 		    &parent) != 0)
 			return (EIO);
 		dd = (dsl_dir_phys_t *)&parent.dn_bonus;
 		child_dir_zapobj = dd->dd_child_dir_zapobj;
-		if (objset_get_dnode(spa, &spa->spa_mos, child_dir_zapobj,
+		if (objset_get_dnode(spa, spa->spa_mos, child_dir_zapobj,
 		    &child_dir_zap) != 0)
 			return (EIO);
 		if (zap_rlookup(spa, &child_dir_zap, component, dir_obj) != 0)
@@ -2983,7 +2986,7 @@
 	dsl_dir_phys_t *dd;
 	const char *p, *q;
 
-	if (objset_get_dnode(spa, &spa->spa_mos,
+	if (objset_get_dnode(spa, spa->spa_mos,
 	    DMU_POOL_DIRECTORY_OBJECT, &dir))
 		return (EIO);
 	if (zap_lookup(spa, &dir, DMU_POOL_ROOT_DATASET, sizeof (dir_obj),
@@ -2992,7 +2995,7 @@
 
 	p = name;
 	for (;;) {
-		if (objset_get_dnode(spa, &spa->spa_mos, dir_obj, &dir))
+		if (objset_get_dnode(spa, spa->spa_mos, dir_obj, &dir))
 			return (EIO);
 		dd = (dsl_dir_phys_t *)&dir.dn_bonus;
 
@@ -3013,7 +3016,7 @@
 		}
 
 		child_dir_zapobj = dd->dd_child_dir_zapobj;
-		if (objset_get_dnode(spa, &spa->spa_mos, child_dir_zapobj,
+		if (objset_get_dnode(spa, spa->spa_mos, child_dir_zapobj,
 		    &child_dir_zap) != 0)
 			return (EIO);
 
@@ -3036,21 +3039,21 @@
 	dsl_dataset_phys_t *ds;
 	dsl_dir_phys_t *dd;
 
-	if (objset_get_dnode(spa, &spa->spa_mos, objnum, &dataset)) {
+	if (objset_get_dnode(spa, spa->spa_mos, objnum, &dataset)) {
 		printf("ZFS: can't find dataset %ju\n", (uintmax_t)objnum);
 		return (EIO);
 	}
 	ds = (dsl_dataset_phys_t *)&dataset.dn_bonus;
 	dir_obj = ds->ds_dir_obj;
 
-	if (objset_get_dnode(spa, &spa->spa_mos, dir_obj, &dir)) {
+	if (objset_get_dnode(spa, spa->spa_mos, dir_obj, &dir)) {
 		printf("ZFS: can't find dirobj %ju\n", (uintmax_t)dir_obj);
 		return (EIO);
 	}
 	dd = (dsl_dir_phys_t *)&dir.dn_bonus;
 
 	child_dir_zapobj = dd->dd_child_dir_zapobj;
-	if (objset_get_dnode(spa, &spa->spa_mos, child_dir_zapobj,
+	if (objset_get_dnode(spa, spa->spa_mos, child_dir_zapobj,
 	    &child_dir_zap) != 0) {
 		printf("ZFS: can't find child zap %ju\n", (uintmax_t)dir_obj);
 		return (EIO);
@@ -3071,7 +3074,7 @@
 	size_t size;
 	int err;
 
-	err = objset_get_dnode(spa, &spa->spa_mos, objnum, &dataset);
+	err = objset_get_dnode(spa, spa->spa_mos, objnum, &dataset);
 	if (err != 0) {
 		printf("ZFS: can't find dataset %ju\n", (uintmax_t)objnum);
 		return (err);
@@ -3079,7 +3082,7 @@
 	ds = (dsl_dataset_phys_t *)&dataset.dn_bonus;
 	dir_obj = ds->ds_dir_obj;
 
-	err = objset_get_dnode(spa, &spa->spa_mos, dir_obj, &dir);
+	err = objset_get_dnode(spa, spa->spa_mos, dir_obj, &dir);
 	if (err != 0) {
 		printf("ZFS: can't find dirobj %ju\n", (uintmax_t)dir_obj);
 		return (err);
@@ -3087,7 +3090,7 @@
 	dd = (dsl_dir_phys_t *)&dir.dn_bonus;
 
 	child_dir_zapobj = dd->dd_child_dir_zapobj;
-	err = objset_get_dnode(spa, &spa->spa_mos, child_dir_zapobj,
+	err = objset_get_dnode(spa, spa->spa_mos, child_dir_zapobj,
 	    &child_dir_zap);
 	if (err != 0) {
 		printf("ZFS: can't find child zap %ju\n", (uintmax_t)dir_obj);
@@ -3125,7 +3128,7 @@
 	dnode_phys_t dataset;
 	dsl_dataset_phys_t *ds;
 
-	if (objset_get_dnode(spa, &spa->spa_mos, objnum, &dataset)) {
+	if (objset_get_dnode(spa, spa->spa_mos, objnum, &dataset)) {
 		printf("ZFS: can't find dataset %ju\n", (uintmax_t)objnum);
 		return (EIO);
 	}
@@ -3155,7 +3158,7 @@
 	/*
 	 * Start with the MOS directory object.
 	 */
-	if (objset_get_dnode(spa, &spa->spa_mos,
+	if (objset_get_dnode(spa, spa->spa_mos,
 	    DMU_POOL_DIRECTORY_OBJECT, &dir)) {
 		printf("ZFS: can't read MOS object directory\n");
 		return (EIO);
@@ -3166,7 +3169,7 @@
 	 */
 	if (zap_lookup(spa, &dir, DMU_POOL_PROPS,
 	    sizeof(props), 1, &props) == 0 &&
-	    objset_get_dnode(spa, &spa->spa_mos, props, &propdir) == 0 &&
+	    objset_get_dnode(spa, spa->spa_mos, props, &propdir) == 0 &&
 	    zap_lookup(spa, &propdir, "bootfs",
 	    sizeof(bootfs), 1, &bootfs) == 0 && bootfs != 0) {
 		*objid = bootfs;
@@ -3177,7 +3180,7 @@
 	 */
 	if (zap_lookup(spa, &dir, DMU_POOL_ROOT_DATASET,
 	    sizeof(root), 1, &root) ||
-	    objset_get_dnode(spa, &spa->spa_mos, root, &dir)) {
+	    objset_get_dnode(spa, spa->spa_mos, root, &dir)) {
 		printf("ZFS: can't find root dsl_dir\n");
 		return (EIO);
 	}
@@ -3248,7 +3251,7 @@
 	size_t size;
 	int rc;
 
-	if ((rc = objset_get_dnode(spa, &spa->spa_mos, DMU_OT_OBJECT_DIRECTORY,
+	if ((rc = objset_get_dnode(spa, spa->spa_mos, DMU_OT_OBJECT_DIRECTORY,
 	    &dir)) != 0)
 		return (rc);
 	if ((rc = zap_lookup(spa, &dir, DMU_POOL_FEATURES_FOR_READ,
@@ -3260,7 +3263,7 @@
 		return (0);
 	}
 
-	if ((rc = objset_get_dnode(spa, &spa->spa_mos, objnum, &dir)) != 0)
+	if ((rc = objset_get_dnode(spa, spa->spa_mos, objnum, &dir)) != 0)
 		return (rc);
 
 	if (dir.dn_type != DMU_OTN_ZAP_METADATA)
@@ -3294,7 +3297,7 @@
 	unsigned char *nv;
 
 	*value = NULL;
-	if ((rc = objset_get_dnode(spa, &spa->spa_mos, obj, &dir)) != 0)
+	if ((rc = objset_get_dnode(spa, spa->spa_mos, obj, &dir)) != 0)
 		return (rc);
 	if (dir.dn_type != DMU_OT_PACKED_NVLIST &&
 	    dir.dn_bonustype != DMU_OT_PACKED_NVLIST_SIZE) {
@@ -3322,22 +3325,23 @@
 static int
 zfs_spa_init(spa_t *spa)
 {
+	struct uberblock checkpoint;
 	dnode_phys_t dir;
 	uint64_t config_object;
 	unsigned char *nvlist;
 	int rc;
 
-	if (zio_read(spa, &spa->spa_uberblock.ub_rootbp, &spa->spa_mos)) {
+	if (zio_read(spa, &spa->spa_uberblock->ub_rootbp, spa->spa_mos)) {
 		printf("ZFS: can't read MOS of pool %s\n", spa->spa_name);
 		return (EIO);
 	}
-	if (spa->spa_mos.os_type != DMU_OST_META) {
+	if (spa->spa_mos->os_type != DMU_OST_META) {
 		printf("ZFS: corrupted MOS of pool %s\n", spa->spa_name);
 		return (EIO);
 	}
 
-	if (objset_get_dnode(spa, &spa->spa_mos, DMU_POOL_DIRECTORY_OBJECT,
-	    &dir)) {
+	if (objset_get_dnode(spa, &spa->spa_mos_master,
+	    DMU_POOL_DIRECTORY_OBJECT, &dir)) {
 		printf("ZFS: failed to read pool %s directory object\n",
 		    spa->spa_name);
 		return (EIO);
@@ -3363,6 +3367,19 @@
 	if (rc != 0)
 		return (rc);
 
+	rc = zap_lookup(spa, &dir, DMU_POOL_ZPOOL_CHECKPOINT,
+	    sizeof(uint64_t), sizeof(checkpoint) / sizeof(uint64_t),
+	    &checkpoint);
+	if (rc == 0 && checkpoint.ub_checkpoint_txg != 0) {
+		memcpy(&spa->spa_uberblock_checkpoint, &checkpoint,
+		    sizeof(checkpoint));
+		if (zio_read(spa, &spa->spa_uberblock_checkpoint.ub_rootbp,
+		    &spa->spa_mos_checkpoint)) {
+			printf("ZFS: can not read checkpoint data.\n");
+			return (EIO);
+		}
+	}
+
 	/*
 	 * Update vdevs from MOS config. Note, we do skip encoding bytes
 	 * here. See also vdev_label_read_config().
Index: stand/lua/core.lua
===================================================================
--- stand/lua/core.lua
+++ stand/lua/core.lua
@@ -38,6 +38,8 @@
 local default_single_user = false
 local default_verbose = false
 
+local bootenv_list = "bootenvs"
+
 local function composeLoaderCmd(cmd_name, argstr)
 	if argstr ~= nil then
 		cmd_name = cmd_name .. " " .. argstr
@@ -270,7 +272,7 @@
 end
 
 function core.bootenvList()
-	local bootenv_count = tonumber(loader.getenv("bootenvs_count"))
+	local bootenv_count = tonumber(loader.getenv(bootenv_list .. "_count"))
 	local bootenvs = {}
 	local curenv
 	local envcount = 0
@@ -281,7 +283,12 @@
 	end
 
 	-- Currently selected bootenv is always first/default
-	curenv = core.bootenvDefault()
+	-- On the rewinded list the bootenv may not exists
+	if core.isRewinded() then
+		curenv = core.bootenvDefaultRewinded()
+	else
+		curenv = core.bootenvDefault()
+	end
 	if curenv ~= nil then
 		envcount = envcount + 1
 		bootenvs[envcount] = curenv
@@ -289,7 +296,7 @@
 	end
 
 	for curenv_idx = 0, bootenv_count - 1 do
-		curenv = loader.getenv("bootenvs[" .. curenv_idx .. "]")
+		curenv = loader.getenv(bootenv_list .. "[" .. curenv_idx .. "]")
 		if curenv ~= nil and unique[curenv] == nil then
 			envcount = envcount + 1
 			bootenvs[envcount] = curenv
@@ -299,6 +306,40 @@
 	return bootenvs
 end
 
+function core.isCheckpointed()
+	return loader.getenv("zpool_checkpoint") ~= nil
+end
+
+function core.bootenvDefaultRewinded()
+	local defname =  "zfs:!" .. string.sub(core.bootenvDefault(), 5)
+	local bootenv_count = tonumber("bootenvs_check_count")
+
+	if bootenv_count == nil or bootenv_count <= 0 then
+		return defname
+	end
+
+	for curenv_idx = 0, bootenv_count - 1 do
+		curenv = loader.getenv("bootenvs_check[" .. curenv_idx .. "]")
+		if curenv == defname then
+			return defname
+		end
+	end
+
+	return loader.getenv("bootenvs_check[0]")
+end
+
+function core.isRewinded()
+	return bootenv_list == "bootenvs_check"
+end
+
+function core.changeRewindCheckpoint()
+	if core.isRewinded() then
+		bootenv_list = "bootenvs"
+	else
+		bootenv_list = "bootenvs_check"
+	end
+end
+
 function core.setDefaults()
 	core.setACPI(core.getACPIPresent(true))
 	core.setSafeMode(default_safe_mode)
Index: stand/lua/menu.lua
===================================================================
--- stand/lua/menu.lua
+++ stand/lua/menu.lua
@@ -132,13 +132,16 @@
 		},
 		{
 			entry_type = core.MENU_ENTRY,
+			visible = function()
+				return core.isRewinded() == false
+			end,
 			name = function()
 				return color.highlight("b") .. "ootfs: " ..
 				    core.bootenvDefault()
 			end,
 			func = function()
 				-- Reset active boot environment to the default
-				config.setCarouselIndex("be_active", 1)
+				config.setcarouselindex("be_active", 1)
 				bootenvSet(core.bootenvDefault())
 			end,
 			alias = {"b", "B"},
@@ -250,6 +253,7 @@
 			},
 			menu_entries.kernel_options,
 			menu_entries.boot_options,
+			menu_entries.zpool_checkpoints,
 			menu_entries.boot_envs,
 			menu_entries.chainload,
 		}
@@ -334,6 +338,32 @@
 			submenu = menu.boot_options,
 			alias = {"o", "O"},
 		},
+		zpool_checkpoints = {
+			entry_type = core.MENU_ENTRY,
+			name = function()
+				rewind = "No"
+				if core.isRewinded() then
+					rewind = "Yes"
+				end
+				return "Rewind ZFS " .. color.highlight("C") ..
+					"heckpoint: " .. rewind
+			end,
+			func = function()
+				core.changeRewindCheckpoint()
+				if core.isRewinded() then
+					bootenvSet(
+					    core.bootenvDefaultRewinded())
+				else
+					bootenvSet(core.bootenvDefault())
+				end
+				config.setCarouselIndex("be_active", 1)
+			end,
+			visible = function()
+				return core.isZFSBoot() and
+				    core.isCheckpointed()
+			end,
+			alias = {"c", "C"},
+		},
 		boot_envs = {
 			entry_type = core.MENU_SUBMENU,
 			visible = function()
Index: sys/cddl/boot/zfs/zfsimpl.h
===================================================================
--- sys/cddl/boot/zfs/zfsimpl.h
+++ sys/cddl/boot/zfs/zfsimpl.h
@@ -1324,6 +1324,7 @@
 #define	DMU_POOL_REMOVING		"com.delphix:removing"
 #define	DMU_POOL_OBSOLETE_BPOBJ		"com.delphix:obsolete_bpobj"
 #define	DMU_POOL_CONDENSING_INDIRECT	"com.delphix:condensing_indirect"
+#define	DMU_POOL_ZPOOL_CHECKPOINT       "com.delphix:zpool_checkpoint"
 
 #define	ZAP_MAGIC 0x2F52AB2ABULL
 
@@ -1787,12 +1788,17 @@
 	char		*spa_name;	/* pool name */
 	uint64_t	spa_guid;	/* pool guid */
 	uint64_t	spa_txg;	/* most recent transaction */
-	struct uberblock spa_uberblock;	/* best uberblock so far */
+	struct uberblock *spa_uberblock;	/* best uberblock so far */
 	vdev_t		*spa_root_vdev;	/* toplevel vdev container */
-	objset_phys_t	spa_mos;	/* MOS for this pool */
+	objset_phys_t	*spa_mos;	/* MOS for this pool */
 	zio_cksum_salt_t spa_cksum_salt;	/* secret salt for cksum */
 	void		*spa_cksum_tmpls[ZIO_CHECKSUM_FUNCTIONS];
 	boolean_t	spa_with_log;	/* this pool has log */
+
+	struct uberblock spa_uberblock_master;  /* best uberblock so far */
+	objset_phys_t    spa_mos_master;        /* MOS for this pool */
+	struct uberblock spa_uberblock_checkpoint;      /* checkpoint uberblock */
+	objset_phys_t    spa_mos_checkpoint;    /* MOS for this pool */
 } spa_t;
 
 /* IO related arguments. */
Index: sys/cddl/contrib/opensolaris/uts/common/fs/zfs/spa.c
===================================================================
--- sys/cddl/contrib/opensolaris/uts/common/fs/zfs/spa.c
+++ sys/cddl/contrib/opensolaris/uts/common/fs/zfs/spa.c
@@ -5695,7 +5695,7 @@
 }
 
 int
-spa_import_rootpool(const char *name)
+spa_import_rootpool(const char *name, bool checkpointrewind)
 {
 	spa_t *spa;
 	vdev_t *rvd, *bvd, *avd = NULL;
@@ -5754,6 +5754,9 @@
 	}
 	spa->spa_is_root = B_TRUE;
 	spa->spa_import_flags = ZFS_IMPORT_VERBATIM;
+	if (checkpointrewind) {
+		spa->spa_import_flags |= ZFS_IMPORT_CHECKPOINT;
+	}
 
 	/*
 	 * Build up a vdev tree based on the boot device's label config.
Index: sys/cddl/contrib/opensolaris/uts/common/fs/zfs/sys/spa.h
===================================================================
--- sys/cddl/contrib/opensolaris/uts/common/fs/zfs/sys/spa.h
+++ sys/cddl/contrib/opensolaris/uts/common/fs/zfs/sys/spa.h
@@ -643,7 +643,7 @@
 #ifdef illumos
 extern int spa_import_rootpool(char *devpath, char *devid);
 #else
-extern int spa_import_rootpool(const char *name);
+extern int spa_import_rootpool(const char *name, bool checkpointrewind);
 #endif
 extern int spa_import(const char *pool, nvlist_t *config, nvlist_t *props,
     uint64_t flags);
Index: sys/cddl/contrib/opensolaris/uts/common/fs/zfs/zfs_vfsops.c
===================================================================
--- sys/cddl/contrib/opensolaris/uts/common/fs/zfs/zfs_vfsops.c
+++ sys/cddl/contrib/opensolaris/uts/common/fs/zfs/zfs_vfsops.c
@@ -1780,6 +1780,18 @@
 	return (0);
 }
 
+static void
+fetch_osname_options(char *name, bool *checkpointrewind)
+{
+
+	if (name[0] == '!') {
+		*checkpointrewind = true;
+		memmove(name, name + 1, strlen(name));
+	} else {
+		*checkpointrewind = false;
+	}
+}
+
 /*ARGSUSED*/
 static int
 zfs_mount(vfs_t *vfsp)
@@ -1790,6 +1802,7 @@
 	char		*osname;
 	int		error = 0;
 	int		canwrite;
+	bool		checkpointrewind;
 
 #ifdef illumos
 	if (mvp->v_type != VDIR)
@@ -1833,6 +1846,7 @@
 		secpolicy_fs_mount_clearopts(cr, vfsp);
 	}
 #endif	/* illumos */
+	fetch_osname_options(osname, &checkpointrewind);
 
 	/*
 	 * Check for mount privilege?
@@ -1918,7 +1932,7 @@
 
 		error = getpoolname(osname, pname);
 		if (error == 0)
-			error = spa_import_rootpool(pname);
+			error = spa_import_rootpool(pname, checkpointrewind);
 		if (error)
 			goto out;
 	}