TNL 12/7 - CNC - System not ready

Hi,
We have an (old but working!) Traub TNL 12/7. I mean, working until last week.
The controller batery died with no warning at all and now, in the startup procedure, it appears the message:
ERRORCODE: 0x82000004
CNC - System Not Ready
TRAUB-MMI will not start up
Press any key to continue.


So,...all the information in the CN (FCA635LCX - FCU6-MU516-12) is lost, i get it.
My question is: How can i restore the information/software? We lost the documentation on a fire and there is not much information online.

Thank you.