Isn't the hall sensor located *under* the LED strip? I haven't touched that part at all.
EDIT:
Okay, went through some disassembly photos of the PW3, and looks like in the attempt to solder the 1.8V line (which I ultimately dropped), I managed to solder over the small resistor at the FL/HALL connector. So little it's barely visible.
The one I'm talking about is just next to the connector's pin that is marked "2", under the last "L" of the "FL/HALL" mark. I'll clean that up and see where I can get with it.