We've received multiple system boards from Dell for 3120 chromebooks and are unable to use the provided shim tool. It errors out saying invalid action when trying to install it.  I've tried just resetting the serial number on the board and I get an error saying Flashrom is in an unknown state. I've removed the bracket and install the write protect screw and it does not work. I contacted support and the only answer was to send the device in.  I would really like to be able to replace system boards myself as it is a faster repair time. Any suggestions?