diff --git a/libisoburn/trunk/xorriso/xorriso_timestamp.h b/libisoburn/trunk/xorriso/xorriso_timestamp.h
index 37160c2a..278170ce 100644
--- a/libisoburn/trunk/xorriso/xorriso_timestamp.h
+++ b/libisoburn/trunk/xorriso/xorriso_timestamp.h
@@ -1 +1 @@
-#define Xorriso_timestamP "2009.08.17.162456"
+#define Xorriso_timestamP "2009.08.17.162834"
diff --git a/libisoburn/trunk/xorriso/xorrisoburn.c b/libisoburn/trunk/xorriso/xorrisoburn.c
index 3d8f0104..d03c48e3 100644
--- a/libisoburn/trunk/xorriso/xorrisoburn.c
+++ b/libisoburn/trunk/xorriso/xorrisoburn.c
@@ -9217,9 +9217,9 @@ int Xorriso_check_interval(struct XorrisO *xorriso, struct SpotlisT *spotlist,
  struct stat stbuf;
  void *ctx= NULL, *cloned_ctx= NULL;
  char md5[16], tag_md5[16];
- uint32_t pos, range_start, range_size, next_tag= 0, lba, md5_spot_lba;
+ uint32_t pos, range_start, range_size, next_tag= 0, lba, md5_spot_lba= 0;
  int md5_spot_value= Xorriso_read_quality_untesteD, chain_broken= 0;
- int tag_type= 0, valid, was_sb_tag= 0;
+ int tag_type= 0, valid, was_sb_tag= 0, in_track_gap= 0;
  char *comparison= "", *sev_text= "DEBUG", *tag_type_name= "";
 
  ret= Xorriso_get_drive_handles(xorriso, &dinfo, &drive,
@@ -9392,13 +9392,32 @@ abort_check:;
                                         &pos, &range_start, &range_size,
                                         &next_tag, tag_md5, !!chain_broken);
          }
-         valid= (ret == 1 || ret == ISO_MD5_AREA_CORRUPTED);
-         if(valid && tag_type == 2 && pos == lba && lba < md5_start + 32) {
+         valid= (ret == 1 || ret == ISO_MD5_AREA_CORRUPTED) && pos == lba;
+         if(valid && tag_type == 2 && (lba < md5_start + 32 || in_track_gap)) {
            tag_type_name= "superblock";
            was_sb_tag= 1;
-         }else if(valid && tag_type == 3 && pos == lba && was_sb_tag) {
+           if(in_track_gap && range_start != md5_start && range_start < lba &&
+              lba - range_start <= j) {
+             /* Looking for next session : start computing in hindsight.
+                Session start and superblock tag are supposed to be in the
+                same 64 kB chunk.
+             */
+             iso_md5_end(&ctx, md5);
+             ret= iso_md5_start(&ctx);
+             if(ret < 0) {
+               Xorriso_no_malloc_memory(xorriso, NULL, 0);
+               ret= -1; goto ex;
+             }
+             iso_md5_compute(&ctx, data + (j - (lba - range_start)) * 2048,
+                             (lba - range_start) * 2048);
+             md5_start= range_start;
+             in_track_gap= 0;
+           }
+         } else if(valid && tag_type == 4 && lba < 32) {
+           tag_type_name= "relocated 64kB superblock";
+         }else if(valid && tag_type == 3 && was_sb_tag) {
            tag_type_name= "tree";
-         }else if(valid && tag_type == 1 && pos == lba) {
+         }else if(valid && tag_type == 1) {
 
            /* >>> ??? allow this without superblock and tree tag ? */
 
@@ -9417,6 +9436,7 @@ abort_check:;
                        (unsigned int) md5_start, range_start);
              Xorriso_msgs_submit(xorriso, 0, xorriso->info_text, 0, "NOTE",0);
              chain_broken= 1;
+             valid= 0;
            } else {
              ret= iso_md5_clone(ctx, &cloned_ctx);
              if(ret <= 0) {
@@ -9450,6 +9470,30 @@ abort_check:;
              Xorriso_msgs_submit(xorriso, 0, xorriso->info_text, 0,
                                  sev_text, 0);
            }
+           if(valid && (tag_type == 1 || 
+                        (tag_type == 4 && pos == lba && lba < 32))) {
+             if(md5_spot_value != Xorriso_read_quality_untesteD) {
+               ret= Spotlist_add_item(spotlist, md5_start,
+                                  md5_spot_lba - md5_start, md5_spot_value, 0);
+               if(ret <= 0)
+               goto ex;
+             }
+             md5_spot_value= Xorriso_read_quality_untesteD;
+             md5_start = lba + 1;
+             if (md5_start % 32)
+                 md5_start= md5_start + (32 - (md5_start % 32));
+             next_tag= 0;
+
+             iso_md5_end(&ctx, md5);
+             ret= iso_md5_start(&ctx);
+             if(ret < 0) {
+               Xorriso_no_malloc_memory(xorriso, NULL, 0);
+               ret= -1; goto ex;
+             }
+             if(tag_type == 1)
+               in_track_gap= 1;
+       continue;
+           }
          }
          iso_md5_compute(ctx, data + j * 2048, 2048);
        }