mBot reversed itself

#1

My mBot was working fine, including using the remote control. Somehow it stopped working with the remote control. I upgraded the firmware and did a restore of the default program and now it works with the remote control except the forward button makes it move backwards and the reverse button makes it move forwards.

It still turns the right directions: The right turn button turns right and the left turn button turns left. The line-follower mode doesn’t work because it is moving backwards.

I did not switch the motor connections!

If I connect it with the USB cable and double-click the ‘run forward at speed 50’ command, it moves backwards. If I double-click the ‘run backward at speed 50’ command, it moves forwards.

#2

Still a mystery. I’m pretty sure this was done in software. I switched the motor connections to be the opposite of the setup instructions (and the opposite of when it was earlier working properly) and once again it works correctly. Some software settings must be surviving through firmware update and reset default program.

So, all is well now but still a mystery.

#3