I tried your steps,but still continued to have a failure of some sort,in this case,I was stuck on "Releasing device interface..",and it would stop there.
But after hours of research,I finally figured out what the problem was,and I'm surprised that no one else has encountered this problem.(Based on my millions of different search criteria's and finding nothing.)
If your having the same issues,(Probably doesn't even have to be the exact same problem I had) then follow these steps before you do sparkys,if your using OSX,that is.I'm not so sure as to why I had the same problem on windows..
Anyways,On a mac,people that have kies installed will most likely encounter this problem until they download the dmg file for kies,open it,and click uninstall. (Rather than move the app to the trash)
Then after that,you have to open up terminal and disable the three kext extensions in association with the connection preventing root to your phone.Like so:
$ sudo kextunload -b com.devguru.driver.SamsungComposite
$ sudo kextunload -b com.devguru.driver.SamsungACMData
$ sudo kextunload -b com.devguru.driver.SamsungACMControl
Then you should be able to do sparkys steps above from beginning to end flawlessly!Hope this helps,seeings as though I had to search for hours and put the pieces together.
