First, this is the old BeagleBoard C2 based, so first are you using a
real externally powered USB 2.0 Hub?
2nd, read about the ehci hardware issue: http://elinux.org/BeagleBoard#EHCI
3rd, care to use an image with ubuntu that is actually supported by
someone now days?
http://elinux.org/BeagleBoardUbuntu#Demo_Image
Note, your board has the bootloader in NAND so you'll have to also follow:
http://elinux.org/BeagleBoardUbuntu#Upgrade_X-loader_and_U-boot
As I guarantee my image will not work with some random bootloader installed..
Regards,