Index: head/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/spa.c
===================================================================
--- head/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/spa.c
+++ head/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/spa.c
@@ -615,9 +615,7 @@
 
 				/*
 				 * Must be ZPL, and its property settings
-				 * must be supported by GRUB (compression
-				 * is not gzip, and large blocks or large
-				 * dnodes are not used).
+				 * must be supported.
 				 */
 
 				if (dmu_objset_type(os) != DMU_OST_ZFS) {
@@ -627,12 +625,6 @@
 				    zfs_prop_to_name(ZFS_PROP_COMPRESSION),
 				    &propval)) == 0 &&
 				    !BOOTFS_COMPRESS_VALID(propval)) {
-					error = SET_ERROR(ENOTSUP);
-				} else if ((error =
-				    dsl_prop_get_int_ds(dmu_objset_ds(os),
-				    zfs_prop_to_name(ZFS_PROP_DNODESIZE),
-				    &propval)) == 0 &&
-				    propval != ZFS_DNSIZE_LEGACY) {
 					error = SET_ERROR(ENOTSUP);
 				} else {
 					objnum = dmu_objset_id(os);
Index: head/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/zfs_ioctl.c
===================================================================
--- head/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/zfs_ioctl.c
+++ head/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/zfs_ioctl.c
@@ -4208,16 +4208,6 @@
 		    intval != ZFS_DNSIZE_LEGACY) {
 			spa_t *spa;
 
-			/*
-			 * If this is a bootable dataset then
-			 * we don't allow large (>512B) dnodes,
-			 * because GRUB doesn't support them.
-			 */
-			if (zfs_is_bootfs(dsname) &&
-				intval != ZFS_DNSIZE_LEGACY) {
-				return (SET_ERROR(EDOM));
-			}
-
 			if ((err = spa_open(dsname, &spa, FTAG)) != 0)
 				return (err);