Fritzbox 3370 Error - no config / Eva not available

I cannot reach Eva during the start-up of the fritzbox.

The box is serially linked. I get the error: <ERROR: no Config - USING Defaultconfig! >
(I give a return after "EVA_AVM>" appears on the screen)

By the way: normal startup with the original avm-software is functioning


Is a file missing?

Someone familiar with this?