For almost anyone, but especially for a student caught in a cycle of failure, the greatest motivator is success. You may have seen the Nike running app that gathers data every time a runner goes out for a jog, then puts it in order and serves it up on a smartphone. Athletes can see how many miles they've run over the course of a year, their personal bests, their average times from week to week, and other data. It's very motivating.
Technology can do the same thing for people learning to read. It can process data and demonstrate improvement in even the smallest increments. And for students who have never experienced success in school, seeing those reading levels tick up and up is incredibly motivating.