I have an old-ish smartphone, a Huawei Rio L03 GX8. I want to give it away, and I’ve done a factory reset. However, after reading articles such as this one ( [fr_most15.pdf (cam.ac.uk)](https://www.cl.cam.ac.uk/~rja14/Papers/fr_most15.pdf) ) I am worried about my data not being safe. Can anyone weigh in on this? I have heard that factory reset ensures that the data is gone for good, but this article seems to claim otherwise.