The bad news: My new phone is defective. It drops USB data connections without warning after a few hundred bytes or so.
The good news: Wirefly is exchanging it without any argument. They're drop-shipping me a new phone, which they promise will be here Tuesday.
I discovered the problem while using Motorola's phone tools to upload contact lists etc to our phones. Contacts, wallpaper, ringtones, they all work fine uploading to Cymru's phone. To mine ... "Data connection was interrupted by phone."