sudomod

I finally found a USB hub that works (one of the octopus style ones from the wiki), but I am noticing something that is different in my build versus wermy's. He wired power and ground for both the external USB port and the microcontroller (Teensy in his case, Arduino in mine) to the PowerBoost and only had the data lines going to the hub. I have tried to do this, but I can only get both the external port and Arduino to work if the power and ground go to the hub instead of the PowerBoost. I have checked with a voltage meter that I am in fact getting power to both when powering via the PowerBoost, and I can also see the light come on on the Arduino (though the TX/RX lights never come on). Again, they work fine when all 4 wires go to the hub. So, my questions are:

1) Am I doing something incorrectly?
2) Is this something specific to this type of hub? I found nothing mentioning it when doing a forum search.
3) Is there any harm in running power through the hub instead of directly from the PowerBoost? I haven't tried with this specific hub just yet, but if I find that I can power the hub from the PowerBoost (it's currently soldered to the power test pads), is it going to make that much difference to power both of these things through the hub instead of directly from the PowerBoost?

Testing further, if I desolder the power and ground for the hub from the Pi test pads and power them from the PowerBoost, I lose USB functionality. I'm seriously at my wit's end here, guys. I could sure use some help.

I get power to the Arduino, so I don't believe it's a power issue. It's like a circuit isn't being completed. I have been stuck on this piece of it for weeks. After finding a hub that would work, I am now stuck at getting the power draw off of the Pi. I could use a little feedback on my questions above. If my post isn't clear, please let me know.

OK. I think it's all about sharing a common ground. In wermy's guide, he uses two different sets of outputs off of the PowerBoost to power everything. I think for the USB to work, ALL of it has to share the same output out of the PowerBoost. The other output can be used for audio and such, if need be, but all USB needs to share a ground in my case.