written data in track one varies from original

Hi, I'm trying to burn a grub-rescue iso image to a cd-rw, and have been 
  getting "written data in track one varies from original" errors.

The output I get is:

System
-----------------------
K3b Version: 1.0.5

KDE Version: 3.5.10
QT Version:  3.3.8b
Kernel:      2.6.31-rc6
Devices
-----------------------
HL-DT-ST DVD-RAM GH22NP20 1.02 (/dev/hdb, ) [CD-R, CD-RW, CD-ROM, 
DVD-ROM, DVD-R, DVD-RW, DVD-R DL, DVD+R, DVD+RW, DVD+R DL] [DVD-ROM, 
DVD-R Sequential, DVD-R Dual Layer Sequential, DVD-R Dual Layer Jump, 
DVD-RAM, DVD-RW Restricted Overwrite, DVD-RW Sequential, DVD+RW, DVD+R, 
DVD+R Dual Layer, CD-ROM, CD-R, CD-RW] [SAO, TAO, RAW, SAO/R96P, 
SAO/R96R, RAW/R16, RAW/R96P, RAW/R96R, Restricted Overwrite, Layer Jump]

K3bDataTrackReader
-----------------------
reading sectors 0 to 641 with sector size 2048. Length: 642 sectors, 
1314816 bytes.
using buffer size of 64 blocks.
Read a total of 642 sectors (1314816 bytes)

K3bMd5Job
-----------------------
Reached max read of 1314816. Stopping after 1314816 bytes.

Used versions
-----------------------
cdrecord: 1.1.9

cdrecord
-----------------------
TOC Type: 1 = CD-ROM
Driveropts: 'burnfree'
Device type    : Removable CD-ROM
Version        : 0
Response Format: 2
Capabilities   :
Vendor_info    : 'HL-DT-ST'
Identification : 'DVD-RAM GH22NP20'
Revision       : '1.02'
Device seems to be: Generic mmc2 DVD-R/DVD-RW.
Current: 0x000A (CD-RW)
Profile: 0x0012 (DVD-RAM)
Profile: 0x002B (DVD+R/DL)
Profile: 0x001B (DVD+R)
Profile: 0x001A (DVD+RW)
Profile: 0x0016 (DVD-R/DL layer jump recording)
Profile: 0x0015 (DVD-R/DL sequential recording)
Profile: 0x0014 (DVD-RW sequential recording)
Profile: 0x0013 (DVD-RW restricted overwrite)
Profile: 0x0011 (DVD-R sequential recording)
Profile: 0x0010 (DVD-ROM)
Profile: 0x000A (CD-RW) (current)
Profile: 0x0009 (CD-R)
Profile: 0x0008 (CD-ROM)
Profile: 0x0002 (Removable disk)
Using generic SCSI-3/mmc   CD-R/CD-RW driver (mmc_cdr).
Driver flags   : MMC-3 SWABAUDIO BURNFREE
Supported modes: TAO PACKET SAO SAO/R96P SAO/R96R RAW/R16 RAW/R96P RAW/R96R
Drive buf size : 1114112 = 1088 KB
scsidev: '/dev/hdb'
devname: '/dev/hdb'
scsibus: -2 target: -2 lun: -2
Linux sg driver version: 3.5.27
Wodim version: 1.1.9
SCSI buffer size: 64512
Beginning DMA speed test. Set CDR_NODMATEST environment variable if device
communication breaks or freezes immediately after that.
Speed set to 706 KB/s
Drive DMA Speed: 105757 kB/s 600x CD 76x DVD
FIFO size      : 12582912 = 12288 KB
Track 01: data     1 MB
Total size:        1 MB (00:08.56) = 642 sectors
Lout start:        1 MB (00:10/42) = 642 sectors
Current Secsize: 2048
ATIP info from disk:
   Indicated writing power: 6
   Reference speed: 2
   Is not unrestricted
   Is erasable
   ATIP start of lead in:  -11078 (97:34/22)
   ATIP start of lead out: 359849 (79:59/74)
   1T speed low:  0 (reserved val  0) 1T speed high:  4
   2T speed low:  0 (reserved val  5) 2T speed high:  0 (reserved val 12)
   power mult factor: 3 5
   recommended erase/write power: 3
   A1 values: 02 3A B0
   A2 values: 5C C6 26
Disk type:    Phase change
Manuf. index: 11
Manufacturer: Mitsubishi Chemical Corporation
Blocks total: 359849 Blocks current: 359849 Blocks remaining: 359207
Starting to write CD/DVD at speed   4.0 in real SAO mode for single session.
Last chance to quit, starting real write in    2 seconds.
    1 seconds.
    0 seconds. Operation starts.
Waiting for reader process to fill input buffer ... input buffer ready.
Performing OPC...
Sending CUE sheet...
Writing pregap for track 1 at -150
Starting new track at sector: 0
Track 01:    0 of    1 MB written.
Track 01:    1 of    1 MB written (fifo 100%) [buf  91%]   0.2x.
Track 01: Total bytes read/written: 1314816/1314816 (642 sectors).
Writing  time:   68.380s
Average write speed   0.1x.
Fixating...
Fixating time:   28.286s
/usr/bin/X11/wodim: fifo had 21 puts and 21 gets.
/usr/bin/X11/wodim: fifo was 0 times empty and 0 times full, min fill 
was 100%.

cdrecord command:
-----------------------
/usr/bin/X11/wodim -v gracetime=2 dev=/dev/hdb speed=4 -dao 
driveropts=burnfree -data -tsize=642s -

The machine is old and slow, but the drive supports burnfree operation.

The same problem has occurred on a faster machine with sata dvd-writer.

Any suggestions welcome.

Arthur.


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