Your schematic doesn't jive with how I'm seeing the board, but I'm going off a little out of focus and then zoomed in grainy image, so could be all kinds of wrong there. You have C1 between pin 4 and L1, but I see C1 between pin 4 and Ground. Then pin 5 connects to L1, which makes the thing more like a DC/DC regulator, similar to how the RT8009, ADP2108 and the like are, but neither of those use a 47uH Inductor on the LX pin, at most a 4.7uH, and they also eventually have the VOUT tied back to the other side of the Inductor. So that circuit is like, but not really like them, and I'd be hesitant to throw one of those in there until I'd reversed the board a little more.
EDIT: That thing might even be something more like the MIC5216, where pin 4 there is an Error output to the MCU. In either case though, the Reg seems like it is getting power and enable, but not putting anything out.
If you knew it was a 3.3v Reg, odds are it probably is but you never know, I'd say inject 3.3v on pin 5 of that thing and see if starts running off of that.