Trouble shooting east bay kit

So I am trying to get my maslow working and I am extremely frustrated. When I set it up like the instructions say the left and right motor are backwards from the settings. Then when I swap the cables on the board up and down are correct, however left and right are still swapped. I think I have tried every firmware I can find with no relief insight. I bought it over a year ago so I can’t return anything.

Next step. Swap out Arduino Mega, I think I have one laying around.

Is there an in-depth explanation for the firmware? I tried to find an x/y invert however couldn’t find anything.

In web control there is a quick setup where you tell it whether you are using an over or under configuration. Sounds like this may not be set. So plug your motors in so left turns the left motor, and right the right motor and then check configuration.