I also downloaded Ubuntu to a thumbdrive. As I recall there is some little widget in the upper right corner of the screen that you have to click on to enable the wireless.
I found I had to do this and everything else, like install programs, every time I tried to run the thing; apparently because no changes were ever made to the image that was being booted. I could create files and put them on the desktop; and the next time I booted the system they were all gone. Anyone have any ideas about THAT?? !
ML/NJ
I have used liveusb-creator with some success (particularly with Fedora images.)
Notice the "persistent storage" option on the window; if you set it to a value, then you will find that much persistent space available to your usb image.
It's been a few months since I used one of these images, but I seem to remember that you could add new packages to them that persist over reboots, and the webpage I reference above also indicates that.
Perhaps with a broadcom wireless chip?
Check some forums...
Broadcom has recently made available some Linux drivers....