Tried many options, but situation did not change.
On device info page it is written:
Unit ID =========
SW version - 7.10
GPS version - 0.00.00
=============
I think that shows that my unit is half dead already?
As far as declared to myself that unit is dead I'm opened for any advices what else could be done in order to bring it to the life from the death .
I have made a copy of reg 41 if that matters and as far as it still insist to be 3490 - a full file system backup.