When I replaced the shell on my P4 I desoldered the motor wires from the ESC boards. When I got it back together it seemed fine, but the motors were spinning backward. The motors responded to throttle commands. On checking it turns out I got the white and black wires reversed for all four motors at the ESC connections. So I corrected that and got it back together. On powering up there were the normal startup sounds and then an error message that the ESCs for 1, 2 and 4 had an error. The LED under motor 1 (right front) did not light up, but the other three did, and after a couple of minutes the three turned red. I tried restarting the P4 and the remote controller and my Nexus 7 tablet, but none of that cured the problem. I removed the camera/gimbal assembly and checked cable connections, but saw nothing wrong. I powered up the P4 without the camera/gimbal on and still got the ESC errors. I put the camera/gimbal back on and tried again, and now there are ESC errors on all 4 motors. The left side LEDs both glow steady red, and right side LEDs don't light up at all. I don't think the brief run with motors wired reversed could have fried the ESC chips, because the motors responded to the throttle even though they were blowing air upward instead of down. What could be the cause and what is the cure?