growisofs and ieee1394 Toshiba SD-R5002 burns bad DVD-Rs

[techt <techt@pikeonline.net>]

I used to be able to burn good DVD-R and DVD-RW discs using growisofs
with a Toshiba SD-R5002 (firmware 1033) in an external firewire case. 
I'm not sure which version of growisofs/mkisofs and Linux kernel I was
using at the time and unfortunately I cannot check since the laptop I
was using then is now broken.  I was using Debian testing with a
2.4.twenty-something kernel.

Recently on another machine, I'd installed Debian testing using kernel
versions 2.4.25, 2.6.3, 2.6.5, and the recent 2.6.6 (unpatched from
kernel.org).  Three different DVD-R brands have been tried: BeAll 1x-4x,
Princo 1x, and a no-name 1x-2x.  All attempts to write to these DVD-Rs
using growisofs (v5.19) using the same Toshiba DVD-RW drive have
resulted in unusable DVD-Rs.  dvd+rw-mediainfo reports:

  INQUIRY:                [TOSHIBA ][DVD-ROM SD-R5002][1033]
  GET [CURRENT] CONFIGURATION:
  :-( no media mounted, exiting...
 
Unwritten DVD-Rs report correct information.  One weird thing is the
written side of these unusable DVD-Rs look very strange.  One can see
concentric circles of light-and-dark in the medium which isn't present
on properly written media.

Currently, I've been writing to DVDs using dvdrecord -dao with iso
images which works even though dvdrecord aborts at the end with an error
when the cache is flushed.