Dell 2155cn, adding a duplexing unit.

I am trying to install a new duplexing unit in my 2155cn. Basically convert it from a 2155cn to a 2155cdn. I had to make a new cable to connect the duplexer to the MCU board. There is a ground point that needs to be added underneath the duplex unit. I have not done that yet. Not sure it has to be done yet.

I am currently getting a 077-217 error code when I connect the duplexer. This says the duplexer is misconfigured. I wonder if there is a firmware update needed to get past this error. I have not seen two part numbers for the MCU board. I have also looked for a setting in the menu with no luck. I also wonder if there is a way to fix this with a service mode configuration.

Any help with this would be greatly appreciated.

Thanks,

Brian