Question is if above is actually complete growisofs command line?Very good question, indeed. Somehow -dvd-compat sneaked into the growisofs_wrapper of scdbackup since i made the last round of media tests. The command line is most probably this: growisofs -use-the-force-luke \ -dvd-compat \ -use-the-force-luke=bufsize:16m \ -use-the-force-luke=noload \ -Z /dev/sr0=/dev/fd/0 which is well entitled to assume the ISO size as full image size if no other hint is available.
Note that in last post I've said "... the only case that would cause the same error..." It holds true even for -dvd-compat recordings. I.e. -dvd-compat would cause the problem in question *only* in DVD+R DL and DVD-R[W] DAO context. It will still allow you to pad DVD+R, DVD-R Incremental, even DVD-R DL recordings, not to mention rewritables... A.