Index: sys/cddl/contrib/opensolaris/uts/common/fs/zfs/vdev_label.c
===================================================================
--- sys/cddl/contrib/opensolaris/uts/common/fs/zfs/vdev_label.c
+++ sys/cddl/contrib/opensolaris/uts/common/fs/zfs/vdev_label.c
@@ -802,7 +802,9 @@
 	}
 
 	/*
-	 * TRIM the whole thing so that we start with a clean slate.
+	 * TRIM the whole thing, excluding the blank space and boot header
+	 * as specified by ZFS On-Disk Specification (section 1.3), so that
+	 * we start with a clean slate.
 	 * It's just an optimization, so we don't care if it fails.
 	 * Don't TRIM if removing so that we don't interfere with zpool
 	 * disaster recovery.
@@ -810,7 +812,8 @@
 	if (zfs_trim_enabled && vdev_trim_on_init && !vd->vdev_notrim && 
 	    (reason == VDEV_LABEL_CREATE || reason == VDEV_LABEL_SPARE ||
 	    reason == VDEV_LABEL_L2CACHE))
-		zio_wait(zio_trim(NULL, spa, vd, 0, vd->vdev_psize));
+		zio_wait(zio_trim(NULL, spa, vd, VDEV_SKIP_SIZE,
+		    vd->vdev_psize - VDEV_SKIP_SIZE));
 
 	/*
 	 * Initialize its label.