Comment 39 for bug 995111

Note that for returning from the special debug modes (forced uni-directional, no re-attaching of the kernel module) you have to give the option names with "-default":

lpadmin -p Canon_iP4200 -R usb-no-reattach-default
lpadmin -p Canon_iP4200 -R usb-unidir-default

Please check whether the modes got actually reset looking for a line containing "Deleting <option>-default" in your error_log. After that do the appropriate test.