I am also not able to calibrate after update to opentx 2.3.1 - have tried on backup model - after found it was not working recreated the model - yaw and throttle will be mixed whatever I do. Could you please provide detailed instructions how to setup the taranis x9d (using opentx 2.3.1) to calibrate fpv freerider on windows 10? The usb driver issue (caused by windows update) was fixed already so that is not at play.
As you go through the calibrate controller procedure, can you see if the yaw and throttle are using individual channels? (If you have a look at the small circles above the ok button you should see if you can move 4 circles individually with the sticks). Sometimes the automatic stick detection gets it wrong, in that case you can click the little circle that you see is the correct one for each channel (instead of clicking ok). I don't own a taranis myself so I'm not going to be able to see exactly what's wrong unfortunately.
That nailed it. The trick is when doing calibration - at the first screen - you center the sticks and click ok.
At first stick detection seems fine, but after that they will affiliate with the wrong circle ;-)
Then for yaw click the 4th circle, throttle the 3rd, pitch the 2nd and finally roll the 1st circle. Hopes this helps also for others. Maybe you could update the manual for the Taranis for future users. Weird problem because the only change was having new Opentx firmware.
Anyway. Now I can fly again !!!