Ok. I'm new to this and my v-tail quad kept flipping on spool up. I searched the forums and found tons of motor configuration issues, rotation, and plugged into the wrong port.
In my case it was the gyro direction that was causing the problem. While checking the set up I noticed that it would accelerate the wrong set of motors to correct for the flip. Went into config.h and defined the gyro directions to compensate and now it works.
Using a HK328p w/DSM and USB with eRC motors and speed controls.
Hope this helps someone with a similar problem.