Car is back home and in perfect condition. Initially service tried to reload from ground up (aka hard boot ?). Didn't work as the software load kept stopping. Then changed some of the coding and still didn't work. Tesla California was able to run remote diagnostics (car is in Florida), and determined the Instrument Cluster was bad. So they ordered one and replaced, reloaded everything with no problems. Picked up today and everything worked great. The IC displays everything properly and the NAV works now for the first time since new (January 17). Only had it back one day, but no screen blank outs so far.