What happened...
Generically speaking, an EEPROM is sometimes used not just to store parameters you are manipulating, but also sometimes it is preloaded with data that isn't normally written by the controlling microprocessor. For example, perhaps there are several sub-models of something on this elevator and they need a slight adjustment from model A to model B to model C -- the software may just store this A/B/C value in the EEPROM when it is first commissioned at the factory and that specific parameter is essentially a read-only value never to be written again. So, in this case, putting in a new EEPROM would require you to read the old one and program the new one with the old data before installing it. Of course, this has a possible downside as well if the old EEPROM has corrupted some things.
If getting a factory replacement is an option that is the best route.
