Revo Mixing and GY401?
I agree completely, never use revo in HH. I will test on mine to see if switching between modes while using revo in normal can cause a fault like you did.
Upon initialization, first the gyro checks to see that it is commanded to be in HH. Then the gyro reads the pulse width of the yaw channel and sets that as neutral. At this point the red led glows steady indicating HH. Switching to normal won't change this preset neutral. In normal mode the gyro functions as any other rate gyro and should benefit from revo mixing as would any other rate gyro. Switching back to HH the gyro reverts back to the previously stored neutral pulsewidth.
This is my understanding and again I admit I may be wrong.
basmntdweller
PS revo mixing is only activated in the tx in normal mode and disabled in HH. You may have revo working and not realize it.
I just played with my 8U and I can't turn revo on and off like I can in my 9C. So, If your radio supports two gyro modes with and without revo you can use it. If your radio doesn't support dual modes, you can't use it at all.
I learn something new everyday!!!