How do I reset the steering command bars on the reversing camera?

I have a disconect device on my 2004 Prius which operates when the aux 12V battery drops to 11.8 volts. It just has, as I went overseas for a couple of months. Touching a button hooks it back in again and all is well apart for the resets required for windows, radio etc. I can work through those OK, all except for restoring the yellow steering command bars when reversing. The rest of the reversing camera is fine but those command bars are really helpful as they predict and display the steering input required. After the 12V battery disconnects, (and I have had about 10 of them over the years), I always have this command bar disappearing trick. They usually re appear after a week or so so clearly there is something that I inadvertantly do that resets them. I am sure it is simple but it still eludes me. Any ideas please?