Flawed Android Factory Reset Failed to Clear Private Data from Smartphones

The infamous factory reset turns out not to be not as secure as once thought for android devices.  These do affect some older versions (2.3.x – 4.3).  So it affects most android phones.
http://thehackernews.com/2015/05/android-factory-reset.html?utm_source=feedburner&utm_medium=feed&utm_campaign=Feed:+TheHackersNews+(The+Hackers+News+-+Security+Blog)&_m=3n.009a.951.bo0ao071vf.jpe&m=1
Here is the research paper containing the study from Laurent Simon and Ross Anderson.

[gview file=”http://www.cl.cam.ac.uk/~rja14/Papers/fr_most15.pdf”]