Factory reset msp432 RevB Silicon

I'm trying to use the factory reset command on RevB silicon using the BSL to remove security settings and clear flash.

The command response indicates BSL Core Message 0x07  "Unknown Command".  All the other commands seem to work OK on the Rev B silicon.  Is this command implemented?  I've added the Command_Factory_Reset to the mailbox.  Is there anything else I need to do?

Thanks

Dan Powell