Pix4flow work well on 3.5.7 and change nothing but fail on 3.6.7 above

ArduCopter Copter 3.6
1

I have got a PIX4FLOW sensor(quit expensive).It has the version of 1.3.1.It has the sonar MATIBOX 1043.

I changed the FLOW_ENABLE on arducopter with firmware 3.6.7. No opt_x opt_y even opt_queue changed and kept 0.

First i thought something i had set wrong so i tried to fix it for a week and nothing happened.

I got my last try on changing the firmware of the Flight control board with 3.5.7.And everything all right. The number of opt_x opt_y appear.

Then i erased the board and reflashed with 3.6.7 or 3.7.0 version,the problem showed up again.

I am totally confused and wonder how to fix this problem. Can i directly observe if the I2C get the pixflow data on 3.6.7 version?

My testing hardware is a PX4v2.
The reason i required to use 3.6.7 is that my quacopter is small with the board MATEKF405 CTR. It has only the ardupilot version of 3.6.7.

I used an arduino board Mega2560 connecting to the pix4flow senser to reach the i2c address 0x42. The data is normal to recieve.

Thanks.Any anything i need to attach, plz reply to me.

2

Same situation here with px4flow updated with correct ardupilot fw, pixhawk 2 with AC 3.6.7. I had reading with old 3.5.7.
With AC 3.6.7 4 out 5 boot I got bad flow health, but sometime it boot without error but no OP data.