sudo /opt/local/bin/port selfupdate
sudo /opt/local/bin/port install truncate

/opt/local/bin/truncate myXGD3backup.iso 8547991552

/Applications/XBoxBurner.app/Contents/MacOS/dvd+rw-mediainfo /dev/rdisk5
(use this command to verify which drive is the DVD writer)
/Applications/XBoxBurner.app/Contents/MacOS/growisofs -use-the-force-luke=dao -use-the-force-luke=break:2086912 -dvd-compat -speed=4 -Z /dev/rdisk5=myXGD3backup.iso
(repace rdisk5 with the correct drive number)

dvd+rw-mediainfo /dev/rdisk5
growisofs -use-the-force-luke=dao -use-the-force-luke=break:2086912 -dvd-compat -speed=4 -Z /dev/rdisk5=myXGD3backup.iso

growisofs -use-the-force-luke=break:2133520 -speed=2 -Z /dev/rdisk5=/Backups/backupFilename.iso

$ md5sum xxx.iso
$ echo count=$(( $(ls -l xxx.iso | awk '{ print $5 }') / 2048 ))  //to output sector range
$ dd if=/dev/sr0 bs=2048 count=yyy | md5sum           //to rip sector range from disc, and verify (yyy is sector count output for above command)

#!/bin/sh
TSIZE="8547991552"
LAYERBREAK="2086912"
BURNSPEED="2" # or 4

TEMPISO="working.iso"

SCRIPT="$0"
PWD=$(pwd)
EXEDIR=${0%/*}

if [ ! $1 ]; then
   echo "usage: $SCRIPT <original.iso>"
   exit 0
fi

ISO="$1"
if [ ! -f $ISO ]; then
   echo "error: $ISO does not exist"
   exit 0
fi

#check file copy
if [ -f $TEMPISO ]; then
   ZI=$(stat -f "%z" "$ISO")
   ZT=$(stat -f "%z" "$TEMPISO")
   if [ "$ZI" -eq "$ZT" ];  then
      SKIP=1
   fi
   if [ "$ZT" -eq "$TSIZE" ];  then
      echo "! working copy exists and is truncated - most likely abgx has already repaired the topology info."
      echo "?force new working copy and abgx check? [Y/n]"
      read a
      if [[ $a != "Y" ]]; then
         SKIPABGX=1
         SKIP=1
      fi
   fi
fi

if [ ! $SKIP ]; then
   echo "> making duplicate working copy ($TEMPISO)"
   EXE=$(which rsync)
   if [ ! -x $EXE ]; then
      echo "! could not find rsync"
      exit 0
   else
      $EXE -v --progress $ISO $TEMPISO
   fi
else
   echo 'working copy exists, skipping duplication'
fi

if [ ! $SKIPABGX ]; then
   #abx check (repair)
   EXE=$(which abgx360)
   if [ ! -x "$EXE" ]; then
      echo "! could not find executable (abgx360)"
      exit 0
   else
      $EXE - -- $TEMPISO
   fi
else
    echo 'skipping abgx verify/patch'
fi


#truncate
EXE="$EXEDIR/truncate"
if [  ! -x $EXE ]; then
   echo "! could not find executable ($EXE)"
   exit 0
fi
ZT=$(stat -f "%z" "$TEMPISO")
if [ "$ZT" -eq "$TSIZE" ]; then
   echo '>skipping truncate, already done'
else
   echo "#original size: $ZT"
#   echo "truncate size: $TSIZE"
#   echo "truncate? [Y/n]"
#   read a
#   if [[ $a == "Y" ]]; then
      $EXE $TEMPISO $TSIZE
      echo '>truncating...'
      ZT=$(stat -f "%z" "$TEMPISO")
      echo "#new size: $ZT"
#   else
#      echo 'user break'
#      exit 0
#   fi
fi

#check media
EXE="$EXEDIR/dvd+rw-mediainfo"
if [  ! -x $EXE ]; then
   echo "! could not find executable ($EXE)"
   exit 0
fi

#check for burner and blank disc
for i in `seq 1 10`;
do
   DVD="/dev/disk"$i
   DVDSTAT=$($EXE $DVD 2>/dev/null)
   if [[ $DVDSTAT =~ "INQUIRY" ]]; then
      BURNER="/dev/rdisk"$i
      echo "found burner at $BURNER"

      if [[ ! $DVDSTAT =~ "Double Layer" ]]; then
         echo 'media is not DVD-DL'
         exit 0
      fi
      if [[ ! $DVDSTAT =~ "blank" ]]; then
         echo 'media is not blank'
         exit 0
      fi
   fi
done

if [ ! $BURNER ]; then
   echo 'error: no DVD burner or no blank media in drive'
   exit 0
fi

#burn it!
EXE="$EXEDIR/growisofs"
if [  ! -x $EXE ]; then
   echo "! could not find executable ($EXE)"
   exit 0
fi

echo "burn? [Y/n]"
read a
if [[ $a == "Y" ]]; then
   echo ' burning'
   CMD="$EXE -use-the-force-luke=dao -use-the-force-luke=break:$LAYERBREAK -dvd-compat -speed=$BURNSPEED -Z $BURNER=$TEMPISO"
   echo $CMD
   $CMD
   echo 'Done Burning!'
else
   echo 'user break'
   exit 0
fi

echo "remove temporary working ISO? [Y/n]"
read a
if [[ $a == "Y" ]]; then
   rm $TEMPISO
   echo 'working copy iso removed!'
else
   exit 0
fi

echo 'Done!'