I think you found the solution - a powered hub. It sounds like you haven't powered the hub form the M2 properly. How did you hook it up?
I have an M2-ATX power supply, connet to a Intel Atom motherboard.
My problem is that USB ports do not get enough power, rather than those on the motherboard.
Touch screen works + my GPS, but if I take my 3G modem or a flash pen, the computer comes with an error that Windows can not recognize the device and it is even if only 3G modem which sits in.
I've tried with a USB hub, with 230V adapter and it works. I made a wire from the M2-ATX 5volt to the USB hub, but it does not work.
Sounds like you hooked the power to the hub correctly, BUT... some hubs need more than 5V. Check the wall wart you cut off to see what it says the output is. It may be 6V, 7V, or something more. If it says 5V, then you should be able to get it working with proper connections. If the hub needs more than 5V, your best bet is to go and buy a different one that will use 5V.
Yes, the hub just need 5v and 3amp