diff --git a/libisoburn/trunk/libisoburn/burn_wrap.c b/libisoburn/trunk/libisoburn/burn_wrap.c
index 7cfbc8d1..c7980ee1 100644
--- a/libisoburn/trunk/libisoburn/burn_wrap.c
+++ b/libisoburn/trunk/libisoburn/burn_wrap.c
@@ -485,6 +485,8 @@ void isoburn_disc_erase(struct burn_drive *drive, int fast)
 {
  int ret;
  struct isoburn *o;
+ enum burn_disc_status s;
+ char zero_buffer[Libisoburn_target_head_sizE];
 
  ret= isoburn_find_emulator(&o, drive, 0);
  if(ret>0) {
@@ -494,9 +496,16 @@ void isoburn_disc_erase(struct burn_drive *drive, int fast)
      return;
    }
    if(o->emulation_mode>0) {
-     ret= isoburn_invalidate_iso(o, 0);
+     s= isoburn_disc_get_status(drive);
+     if(s==BURN_DISC_FULL) { /* unknown data format in first 64 kB */
+       memset(zero_buffer, 0, Libisoburn_target_head_sizE);
+       ret= burn_random_access_write(drive, (off_t) 0, zero_buffer,
+                                     (off_t) Libisoburn_target_head_sizE, 1);
+     } else {
+       ret= isoburn_invalidate_iso(o, 0);
+     }
      if(ret<=0)
-       burn_drive_cancel(drive);
+       burn_drive_cancel(drive); /* mark run as failure */
      return;
    }
  }
@@ -510,12 +519,16 @@ off_t isoburn_disc_available_space(struct burn_drive *d,
  int ret;
  struct isoburn *o;
  struct burn_write_opts *eff_opts= NULL, *local_opts= NULL;
+ enum burn_disc_status s;
  off_t avail;
 
  eff_opts= opts;
  ret= isoburn_find_emulator(&o, d, 0);
  if(ret>0 && o!=NULL)
    if(o->emulation_mode!=0) {
+     s= isoburn_disc_get_status(d);
+     if(s==BURN_DISC_FULL) /* unknown data format in first 64 kB */
+       return((off_t) 0);
      local_opts= burn_write_opts_new(d);
      eff_opts= local_opts;
      burn_write_opts_set_start_byte(eff_opts, ((off_t) o->nwa) * (off_t) 2048);
diff --git a/libisoburn/trunk/libisoburn/isoburn.c b/libisoburn/trunk/libisoburn/isoburn.c
index 0ee32746..cec63808 100644
--- a/libisoburn/trunk/libisoburn/isoburn.c
+++ b/libisoburn/trunk/libisoburn/isoburn.c
@@ -121,7 +121,7 @@ int isoburn_new(struct isoburn **objpt, int flag)
  o->fabricated_disc_status= BURN_DISC_UNREADY;
  o->toc= NULL;
  o->wrote_well= -1;
- for(i=0;i<65536;i++)
+ for(i=0;i<Libisoburn_target_head_sizE;i++)
    o->target_iso_head[i]= 0;
  o->image= NULL;
  o->read_pacifier= NULL;
diff --git a/libisoburn/trunk/libisoburn/isoburn.h b/libisoburn/trunk/libisoburn/isoburn.h
index 850d3288..129507a7 100644
--- a/libisoburn/trunk/libisoburn/isoburn.h
+++ b/libisoburn/trunk/libisoburn/isoburn.h
@@ -33,6 +33,11 @@ int isoburn_toc_entry_new(struct isoburn_toc_entry **objpt,
 int isoburn_toc_entry_destroy(struct isoburn_toc_entry **o, int flag);
 
 
+/* Size of target_iso_head which is to be written during
+   isoburn_activate_session()
+*/
+#define Libisoburn_target_head_sizE (32*2048)
+
 struct isoburn {
 
 
@@ -89,7 +94,7 @@ struct isoburn {
  
  /* Buffered ISO head from media (should that become part of
     ecma119_read_opts ?) */
- uint8_t target_iso_head[65536];
+ uint8_t target_iso_head[Libisoburn_target_head_sizE];
 
  /* Libisofs image context */
  IsoImage *image;
@@ -368,12 +373,7 @@ struct isoburn_imgen_opts {
 #define Libisoburn_toc_scan_max_gaP 8192
 
 
-/* Size of target_iso_head which is to be written during
-   isoburn_activate_session()
-*/
-#define Libisoburn_target_head_sizE (32*2048)
-
-/* >>> Experiment to create a chain of image headers which form a TOC:
+/* Creating a chain of image headers which form a TOC:
 
    The header of the first session is written after the LBA 0 header.
    So it persists and can give the end of its session. By help of
diff --git a/libisoburn/trunk/libisoburn/isofs_wrap.c b/libisoburn/trunk/libisoburn/isofs_wrap.c
index 8d94777d..ff393fa2 100644
--- a/libisoburn/trunk/libisoburn/isofs_wrap.c
+++ b/libisoburn/trunk/libisoburn/isofs_wrap.c
@@ -283,7 +283,7 @@ int isoburn_activate_session(struct burn_drive *drive)
         o->zero_nwa > 0)))
    return 1;
  
- ret = burn_random_access_write(drive, 0, (char*)o->target_iso_head, 
+ ret = burn_random_access_write(drive, (off_t) 0, (char*)o->target_iso_head, 
                                 Libisoburn_target_head_sizE, 1);
 
  return ret;
@@ -315,7 +315,7 @@ int isoburn_start_emulation(struct isoburn *o, int flag)
  /* we can assume 0 as start block for image */
  /* TODO what about ms? where we validate valid iso image in ms disc? */
  ret = burn_read_data(drive, (off_t) 0, (char*)o->target_iso_head, 
-                      sizeof(o->target_iso_head), &data_count, 2);
+                      (off_t) Libisoburn_target_head_sizE, &data_count, 2);
 
  /* an error means an empty disc */
  if (ret <= 0) {
@@ -325,7 +325,7 @@ int isoburn_start_emulation(struct isoburn *o, int flag)
 
  /* check first 64K. If 0's, the disc is treated as a blank disc, and thus
     overwritten without extra check. */
- i = sizeof(o->target_iso_head);
+ i = Libisoburn_target_head_sizE;
  while (i && !o->target_iso_head[i-1]) 
    --i;
 
diff --git a/libisoburn/trunk/xorriso/xorriso.1 b/libisoburn/trunk/xorriso/xorriso.1
index 66adf44e..2f0caf11 100644
--- a/libisoburn/trunk/xorriso/xorriso.1
+++ b/libisoburn/trunk/xorriso/xorriso.1
@@ -184,7 +184,8 @@ Closed is the state of DVD-ROM media and of multi-session media which were
 written with option -close on. If the drive is incapable of writing it will
 probably show any media as closed CD-ROM resp. DVD-ROM.
 .br
-Overwriteable media assume this state only in such read-only drives.
+Overwriteable media assume this state in such read-only drives or if they
+contain unrecognizable data in the first 32 data blocks.
 .br
 \fBRead-only\fR drives may or may not show session histories of multi-session
 media. Often only the first and the last session are visible. Sometimes
diff --git a/libisoburn/trunk/xorriso/xorriso_timestamp.h b/libisoburn/trunk/xorriso/xorriso_timestamp.h
index a8c46f24..01bf3fca 100644
--- a/libisoburn/trunk/xorriso/xorriso_timestamp.h
+++ b/libisoburn/trunk/xorriso/xorriso_timestamp.h
@@ -1 +1 @@
-#define Xorriso_timestamP "2008.05.13.115901"
+#define Xorriso_timestamP "2008.05.13.135251"
diff --git a/libisoburn/trunk/xorriso/xorrisoburn.c b/libisoburn/trunk/xorriso/xorrisoburn.c
index 6acfc8f9..13ff23e6 100644
--- a/libisoburn/trunk/xorriso/xorrisoburn.c
+++ b/libisoburn/trunk/xorriso/xorrisoburn.c
@@ -928,7 +928,7 @@ int Xorriso_write_session(struct XorrisO *xorriso, int flag)
                "-indev differs from -outdev and -outdev media is not blank");
      else
        sprintf(xorriso->info_text,
-        "-indev differs from -outdev and -outdev media holds valid ISO image");
+          "-indev differs from -outdev and -outdev media holds non-zero data");
      Xorriso_msgs_submit(xorriso, 0, xorriso->info_text, 0, "FAILURE", 0);
      {ret= 0; goto ex;}
    }
@@ -2260,7 +2260,7 @@ int Xorriso_toc(struct XorrisO *xorriso, int flag)
  int num_sessions= 0, num_tracks= 0, lba= 0, nwa= -1, pmin, psec, pframe, ret;
  int track_count= 0, session_no, track_no, profile_no= -1, track_size;
  int last_track_start= 0, last_track_size= -1, num_data= 0, is_data= 0;
- int is_inout_drive= 0, drive_role;
+ int is_inout_drive= 0, drive_role, status, num_formats;
  int num_payload= 0, num_wasted= 0, num_nondata= 0;
  char profile_name[80],*respt,*devadr;
  struct burn_toc_entry toc_entry;
@@ -2268,7 +2268,8 @@ int Xorriso_toc(struct XorrisO *xorriso, int flag)
  struct burn_drive *drive;
  enum burn_disc_status s;
  char mem_text[80];
- off_t start_byte= 0, num_free= 0;
+ off_t start_byte= 0, num_free= 0, size;
+ unsigned dummy;
 
 #ifdef Xorriso_use_isoburn_toC
  struct isoburn_toc_disc *disc= NULL;
@@ -2385,6 +2386,11 @@ int Xorriso_toc(struct XorrisO *xorriso, int flag)
      sprintf(respt, "ISO session  : %3d , %9d , %9ds , %s\n",
              1, 0, image_blocks, volume_id);
    } else {
+     nwa= 0;
+     ret= burn_disc_get_formats(drive, &status, &size, &dummy,
+                                &num_formats);
+     if(ret>0 && status==BURN_FORMAT_IS_FORMATTED)
+       nwa= size/2048;
      sprintf(respt, "Other session: %3d , %9d , %9ds , \n",
              1, 0, nwa);
    }