After a crash, total rebuild with new motherboard and shells, my quad now will flip over on start up when I try to lift off, props are on correctly and all flight checks are done prior to attempts, all lights are good and get green flashing light for sat lock, have checked IMU and is also good to go, when I hold it up and start the motors and then increase speed( with props on and outdoors) the quad tries to either flip forward or backward and not rise, is this a GPS/gyro problem? Or did I not hook the ribbon wires up to the flight controller properly? any one have pics on this, my bad as I should have taken them myself......