I found that when doing the SIII it will error on first attempt using Cable A with Tip T-133 so instead of disconnecting device and going through the motions again I just hit continue. I found this works half of the time. If that does not work I resort to just unplugging device from UFED Touch and just plugging it right back in. At this point, the UFED Touch is usually extracting the device for me. Sometimes I have to do this several times and/or after a few attempts go back through the motions followed by above. I have observed through my career as an examiner that cellular devices are the most finicky little (insert your chose of negative term here) and what works on one does not always work on the same again. I had a SII that failed to connect through five days worth of tries only to connect fine on that fifth day. The funny thing was I performed the same connection method that day as I did the previous days. I guess the DIGITAL GODS smiled on me that day who knows but I can tell you this career takes a lot of patience. Good luck!
You can a physical by JTAG.
http//articles.forensicfocus.com/2014/03/11/jtag-sch-r530u-that-has-android-4-3-on-it/