have been testing an imaging setup that disables usb storage, this to circumvent cleaning out accidentally attached drives.
i tried 2 options, through the cmds by adding 'brokenmodules=usb-storage' & through script by adding 'modprobe -r usb-storage'.
Both have the same effect, that although the usb storage isn't loaded, the usbsignal still triggers something, which in turn breaks the img command with a segmentation fault. Removing the ub device fixes this.

We're using the march 2009 kernel image.