diff --git a/drivers/mtd/ubi/attach.c b/drivers/mtd/ubi/attach.c
index 62d611310..cb2d041b5 100644
--- a/drivers/mtd/ubi/attach.c
+++ b/drivers/mtd/ubi/attach.c
@@ -893,10 +893,9 @@ static int scan_peb(struct ubi_device *ubi, struct ubi_attach_info *ai,
 		 * number.
 		 */
 		image_seq = be32_to_cpu(ech->image_seq);
-		if (!ubi->image_seq && image_seq)
+		if (!ubi->image_seq)
 			ubi->image_seq = image_seq;
-		if (ubi->image_seq && image_seq &&
-		    ubi->image_seq != image_seq) {
+		if (image_seq && ubi->image_seq != image_seq) {
 			ubi_err("bad image sequence number %d in PEB %d, expected %d",
 				image_seq, pnum, ubi->image_seq);
 			ubi_dump_ec_hdr(ech);
@@ -1397,9 +1396,11 @@ int ubi_attach(struct ubi_device *ubi, int force_scan)
 				ai = alloc_ai("ubi_aeb_slab_cache2");
 				if (!ai)
 					return -ENOMEM;
-			}
 
-			err = scan_all(ubi, ai, UBI_FM_MAX_START);
+				err = scan_all(ubi, ai, 0);
+			} else {
+				err = scan_all(ubi, ai, UBI_FM_MAX_START);
+			}
 		}
 	}
 #else
diff --git a/drivers/mtd/ubi/fastmap.c b/drivers/mtd/ubi/fastmap.c
index 939e5346f..1ba157149 100644
--- a/drivers/mtd/ubi/fastmap.c
+++ b/drivers/mtd/ubi/fastmap.c
@@ -406,6 +406,7 @@ static int scan_pool(struct ubi_device *ubi, struct ubi_attach_info *ai,
 	 */
 	for (i = 0; i < pool_size; i++) {
 		int scrub = 0;
+		int image_seq;
 
 		pnum = be32_to_cpu(pebs[i]);
 
@@ -424,10 +425,16 @@ static int scan_pool(struct ubi_device *ubi, struct ubi_attach_info *ai,
 		} else if (ret == UBI_IO_BITFLIPS)
 			scrub = 1;
 
-		if (be32_to_cpu(ech->image_seq) != ubi->image_seq) {
+		/*
+		 * Older UBI implementations have image_seq set to zero, so
+		 * we shouldn't fail if image_seq == 0.
+		 */
+		image_seq = be32_to_cpu(ech->image_seq);
+
+		if (image_seq && (image_seq != ubi->image_seq)) {
 			ubi_err("bad image seq: 0x%x, expected: 0x%x",
 				be32_to_cpu(ech->image_seq), ubi->image_seq);
-			err = UBI_BAD_FASTMAP;
+			ret = UBI_BAD_FASTMAP;
 			goto out;
 		}
 
@@ -808,6 +815,10 @@ static int ubi_attach_fastmap(struct ubi_device *ubi,
 	list_for_each_entry_safe(tmp_aeb, _tmp_aeb, &lfree, u.list)
 		list_move_tail(&tmp_aeb->u.list, &ai->free);
 
+	ubi_assert(list_empty(&used));
+	ubi_assert(list_empty(&eba_orphans));
+	ubi_assert(list_empty(&lfree));
+
 	/*
 	 * If fastmap is leaking PEBs (must not happen), raise a
 	 * fat warning and fall back to scanning mode.
@@ -823,6 +834,19 @@ static int ubi_attach_fastmap(struct ubi_device *ubi,
 fail_bad:
 	ret = UBI_BAD_FASTMAP;
 fail:
+	list_for_each_entry_safe(tmp_aeb, _tmp_aeb, &used, u.list) {
+		free(tmp_aeb);
+		list_del(&tmp_aeb->u.list);
+	}
+	list_for_each_entry_safe(tmp_aeb, _tmp_aeb, &eba_orphans, u.list) {
+		free(tmp_aeb);
+		list_del(&tmp_aeb->u.list);
+	}
+	list_for_each_entry_safe(tmp_aeb, _tmp_aeb, &lfree, u.list) {
+		free(tmp_aeb);
+		list_del(&tmp_aeb->u.list);
+	}
+
 	return ret;
 }
 
@@ -911,6 +935,8 @@ int ubi_scan_fastmap(struct ubi_device *ubi, struct ubi_attach_info *ai,
 	}
 
 	for (i = 0; i < used_blocks; i++) {
+		int image_seq;
+
 		pnum = be32_to_cpu(fmsb->block_loc[i]);
 
 		if (ubi_io_is_bad(ubi, pnum)) {
@@ -928,10 +954,17 @@ int ubi_scan_fastmap(struct ubi_device *ubi, struct ubi_attach_info *ai,
 		} else if (ret == UBI_IO_BITFLIPS)
 			fm->to_be_tortured[i] = 1;
 
+		image_seq = be32_to_cpu(ech->image_seq);
 		if (!ubi->image_seq)
-			ubi->image_seq = be32_to_cpu(ech->image_seq);
+			ubi->image_seq = image_seq;
 
-		if (be32_to_cpu(ech->image_seq) != ubi->image_seq) {
+		/*
+		 * Older UBI implementations have image_seq set to zero, so
+		 * we shouldn't fail if image_seq == 0.
+		 */
+		if (image_seq && (image_seq != ubi->image_seq)) {
+			ubi_err("wrong image seq:%d instead of %d",
+				be32_to_cpu(ech->image_seq), ubi->image_seq);
 			ret = UBI_BAD_FASTMAP;
 			goto free_hdr;
 		}
@@ -1338,7 +1371,7 @@ out:
 static int invalidate_fastmap(struct ubi_device *ubi,
 			      struct ubi_fastmap_layout *fm)
 {
-	int ret, i;
+	int ret;
 	struct ubi_vid_hdr *vh;
 
 	ret = erase_block(ubi, fm->e[0]->pnum);
@@ -1355,9 +1388,6 @@ static int invalidate_fastmap(struct ubi_device *ubi,
 	vh->sqnum = cpu_to_be64(ubi_next_sqnum(ubi));
 	ret = ubi_io_write_vid_hdr(ubi, fm->e[0]->pnum, vh);
 
-	for (i = 0; i < fm->used_blocks; i++)
-		ubi_wl_put_fm_peb(ubi, fm->e[i], i, fm->to_be_tortured[i]);
-
 	return ret;
 }
 
diff --git a/drivers/mtd/ubi/wl.c b/drivers/mtd/ubi/wl.c
index d0d3c97ec..34e23b3d5 100644
--- a/drivers/mtd/ubi/wl.c
+++ b/drivers/mtd/ubi/wl.c
@@ -572,10 +572,6 @@ static void refill_wl_user_pool(struct ubi_device *ubi)
 	return_unused_pool_pebs(ubi, pool);
 
 	for (pool->size = 0; pool->size < pool->max_size; pool->size++) {
-		if (!ubi->free.rb_node ||
-		   (ubi->free_count - ubi->beb_rsvd_pebs < 1))
-			break;
-
 		pool->pebs[pool->size] = __wl_get_peb(ubi);
 		if (pool->pebs[pool->size] < 0)
 			break;
@@ -1020,6 +1016,9 @@ static int wear_leveling_worker(struct ubi_device *ubi, struct ubi_work *wrk,
 		if (!(e2->ec - e1->ec >= UBI_WL_THRESHOLD)) {
 			dbg_wl("no WL needed: min used EC %d, max free EC %d",
 			       e1->ec, e2->ec);
+
+			/* Give the unused PEB back */
+			wl_tree_add(e2, &ubi->free);
 			goto out_cancel;
 		}
 		self_check_in_wl_tree(ubi, e1, &ubi->used);