The MFSYS25 keeps a copy of the configuration on an SD card on the midplane, so swapping CMMs won't reset IP or password. You did find the right web document to follow, though. If you can't get the prompt to respond, check the note at the bottom of that page:
If you see the boot process, but cannot get the EBF prompt, please note that the serial cable or USB to serial cable must be a fully populated straight through cable. Specifically, it must allow the host PC to assert the CTS pin on the CMM.