Well hell. After having my Pro1 on Verizon for 10 months - with no problems - as of a few days ago the dreaded "Mobile Network Not Available" message suddenly appeared. I check network settings, did a factory reset, removed/reinserted the sim card, and then took it into a local Verizon store to see if they could get the phone recognized on their network again. The sales person was less than helpful, saying...
"IMEI isn't recognized on Verizon"
"A network update means you can't use the phone now...want to buy a new one?"
"Are you sure this phone was working on our network