The Auto A/Auto B option has been removed from most "dumb" phones a couple of years ago. I guess they finally got around to removing it from the BB. What it does is: If no system from the PRL (Preferred Roaming List) in the phone can be found, AND the PRL has the "Preferred Only" flag is not set, THEN look on the cellular A or B band (for Auto A / Auto B respectively) for service. This was a feature from the analog days before they had PRLs, to tell the phone where to find service.The PRL for current VZW plans sets the "Preferred Only" flag, so it is irrelevant for them, and the option is not offerred. There are some long-deprecated plans (such as America Choice I) which allows off-PRL roaming. If you dial 911, then the PRL restrictions are ignored, and the phone searches for any system its hardware supports. This has the odd effect that your phone may say "No Service", but a 911 call may go through.
When moving to another provider, you need to do whatever their process is to get their PRL on your phone, so the phone will find their system.
