Hi Christer I don't think there is a fix. Best workaround is to fight the roll, or use a mount that's designed for chopper work. M5 is just not a great fit for chopper ops.
Well, apart from a old Tyler mini gyro rig, i dont know what would be better for chopper work. I got a tip of putting the heading in gps mode, let it sit in the open for 10 min till it get a good gps fix, and then takeoff... will be up next time weather is good, and see how it works...