Hi Rick, first of all: Is it V1 or V1.5? Does the unit still boot? If yes start Settings -> System Information (in the section with the gear wheel) and see which firmware the unit reports: For V1 this reads OS 2.4.50 and SW 2.3.63 and for V1.5 this should read OS version 2.4.50, SW version 2.3.74. Hopefully you waited at least 10 minutes before removing the dongle from power and therefore the updater could do its work in the background. In this case just ignore the "hickup" from the OTA installer. Another update (Android Auto update) will come shortly.
Bye for now Fred
There is a circle that fills in after the update is finished. Once that is filled in, you can unplug and then re-insert and it will continue optimizing. It is best to not remove the device though if you can wait.
@ap756 OK it looks like it updated but I'm not getting any text on the screen.
install "Mirroid" and start it. Then connect Cardongle to the USB of your computer and wait for a start. Take your time (can be up to 5 minutes for boot up). If it works in the emulator try it again in your car.
Bye for now. Fred