Something that has plagued me the past few days when trying to transfer my data from my old phone to my new phone is the fact that I seemed to have lost root privileges on my old Samsung Infuse 4G. This prevented me from being able to use Titanium Backup to backup the data for a few select apps and transfer them to my new SGIII.
I had already flashed a Jellybean ROM called Cypher on my old phone (which came with root access). Unfortunately, I think after an update to the SuperSU (and me messing with its settings trying to get it to work properly), I lost root access. Luckily I was able to access CWM just fine in recovery mode, so that made things easy to re-flash. However, I didn’t feel like re-flashing the entire ROM again. I just wanted a simple fix, so I attempted to just flash versions of Superuser or SuperSU.
Unfortunately, I was not able to get any of these flashes to work and register su. After some digging around, I found out the commands to manually copy su over to your phone via adb.
However, these instructions presupposed that you had either Froyo or Gingerbread Infuse phones to begin with. su is supposed to live in /system/bin for those Android versions. But with the onset of Jellybean, su now lives in /system/xbin . As soon as I followed the manual instructions to push su to /system/xbin I was able to gain the root access I needed.