Without getting a notification, I manually checked for availability of the 2.1 update via SETTINGS - ABOUT PHONE - SYSTEMS UPDATE which showed it was available and asked if I wanted to download it. I selected "yes," and then watched the download progress status bar not move for 45 minutes. Not being able to exit this screen and not wanting to brick the phone, I called Verizon Tech Support. The woman I spoke to had no idea about a Droid 2.1 update. She told me all she could suggest is to pull the battery. I asked if -- since the phone was stuck in the middle of an update -- doing so might brick the phone. She replied that she didn't know what else to suggest. She then told me the update had nothing to do with Verizon anyway and was really a Motorola issue. I asked if there was someone she could check with about this. A short while later she returned to tell me to continue to wait with the non-responsive download bar for at least two more hours because that's a normal download time.
Eventually the phone stopped trying to download the update on its own. A few hours later I tried again and it downloaded in about two minutes. I assume that even even though SYSTEMS UPDATE said I could update, the download really wasn't ready which is why I didn't get the regular update notification. All of this is fine. What's frustrating is the obliviousness of Tech Support.
