Mine did this last season was, told by the dealer that a crystal went out on one side. They sent a new transducer and it fixed the issue

The update 2.28 needs a base map update also otherwise the unit looses all base map possibly. So if doing the newest 2.66 then should do the 2.28 update to get the new base maps before installing the current update

Good morning was wondering if the gragh is still available? Would be interested in it if it is