diff --git a/xorriso/write_run.c b/xorriso/write_run.c
index 5fd688a5..542878e2 100644
--- a/xorriso/write_run.c
+++ b/xorriso/write_run.c
@@ -1989,6 +1989,9 @@ int Xorriso_update_iso_lba0(struct XorrisO *xorriso, int iso_lba, int isosize,
  struct burn_drive_info *dinfo;
  struct burn_drive *drive;
  off_t seek_ret;
+ int tag_type;
+ uint32_t pos, range_start, range_size, next_tag;
+ char md5[16];
 
  ret= Xorriso_may_burn(xorriso, 0);
  if(ret <= 0)
@@ -2040,6 +2043,14 @@ int Xorriso_update_iso_lba0(struct XorrisO *xorriso, int iso_lba, int isosize,
        Xorriso_msgs_submit(xorriso, 0, xorriso->info_text, errno, "FAILURE",0);
        return(0);
      }
+     ret= isoburn_read_iso_head(drive, 0, &isosize, head_buffer, 1 << 13);
+     if(ret<=0) {
+       Xorriso_process_msg_queues(xorriso,0);
+       sprintf(xorriso->info_text,
+               "Alleged session start does not like ISO 9660.");
+       Xorriso_msgs_submit(xorriso, 0, xorriso->info_text, errno, "FAILURE",0);
+       return(0);
+     }
    } else {
      ret= isoburn_read_iso_head(drive, iso_lba, &isosize, head_buffer, 2);
      if(ret<=0) {
@@ -2057,6 +2068,22 @@ int Xorriso_update_iso_lba0(struct XorrisO *xorriso, int iso_lba, int isosize,
  for(i=0;i<4;i++)
    headpt[87-i]= headpt[80+i]= (full_size >> (8*i)) & 0xff;
 
+
+ /* Invalidate eventual libisofs checksum tags */
+ /* Look for volume descriptor end */
+ for(i= 16; i < 32; i++)
+   if(((unsigned char *) head_buffer)[i * 2048] == 0xff &&
+      strncmp(head_buffer + i * 2048 + 1, "CD001", 5) == 0)
+ break;
+ /* Check whether the next one is a libisofs checksum tag */
+ if(i < 32) {
+   i++;
+   ret= iso_util_decode_md5_tag(head_buffer + i * 2048, &tag_type, &pos,
+                                &range_start, &range_size, &next_tag, md5, 0);
+   if(ret != 0) /* corrupted or not: invalidate */
+     memset(head_buffer + i * 2048, 0, 8);
+ }
+
  if(job != NULL) {
    seek_ret= lseek(job->data_to_fd, (off_t) 0, SEEK_SET);
    if(seek_ret == -1)
diff --git a/xorriso/xorriso_timestamp.h b/xorriso/xorriso_timestamp.h
index cee7efbe..7aeadf51 100644
--- a/xorriso/xorriso_timestamp.h
+++ b/xorriso/xorriso_timestamp.h
@@ -1 +1 @@
-#define Xorriso_timestamP "2010.06.16.105449"
+#define Xorriso_timestamP "2010.06.16.105652"