Downgrading USB High Speed

I am running Angstrom (2.6.32) on BeagleBoard-xM rev C. I want to
downgrade USB port from high speed to full speed. I couldn't find any
ehci-hcd kernel module to remove. How can I downgrade my USB ports?

by using external USB-hub. No othet way

Wait a second! XM already supports both HS & LS devices

I know it supports.

I have an UVC web camera which has known problems on high speed mode.
I want to force it to work on full speed mode (i.e. FS, not LS).