It has been a common misconception that a properly BURNED ISO BACKUP could only be duplicated by placing the existing BACKUP in the XBOX, and using FTP to Draw the contents to the PC, and REBUILD using recommended methods. This is simply not so.
UDF Method has long held the advantage of being the only way to burn an XBOX Backup that will RE-READ in a PC. Which is still TRUE? in UDF you have full READ access to the files, to do with as you wish (such as make a duplicate backup). Well? you can Burn your PROPER GDF ISO?s, and even your alternative ISO formats like XISO formatted ISO?s, and make a copy using only the PC.
if you have an xISO too big to fit on a CD-RW and you dont have a DVD burner
but want to install it on xbox via FTP
try ISO Reader
the program will read Xiso's on your pc
that way you'll extract the files
and then install to xbox like regular files (default.xbe etc etc)
Yesterday I placed my first backup, back on my PC with a copy of Record Now Max Plat. edition. The files looked identical in size. I am going to burn a copy from there to see if it is a good extraction.