Title says it all. It worked at first, but then stopped. Could this board be fried? The shutdown URL also sends the command, but it never actually shuts down.
I may have a solution for you:
If you have a Pi-4 and tried a firmware update, your board will become inoperative.
Replacing the Pi with a Pi-3 or earlier and re-flashing the firmware, (after selecting “GoPiGo3” as the robot type), should return the robot to fully operational.
You can try this solution even if you did not flash your board with a Pi-4.
Please let us know what happens.
@jimrh this post was from almost a year ago. Back then there was no issue with the firmware flashing.