1 files changed, 19 insertions, 3 deletions

diff --git a/drivers/mtd/ubi/fastmap.c b/drivers/mtd/ubi/fastmap.c
index 9b42add0553c..05067f522476 100644
--- a/drivers/mtd/ubi/fastmap.c
+++ b/drivers/mtd/ubi/fastmap.c
@@ -407,6 +407,7 @@ 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]);
 
@@ -425,7 +426,13 @@ 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);
                         ret = UBI_BAD_FASTMAP;
@@ -923,6 +930,8 @@ 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)) {
@@ -940,10 +949,17 @@ 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;
                 }