2016 F36 435xi here. Exhaust valve logic for other F3x does not equate to F36. Tried everything, and CANNOT get the valve to open. If there's another '16 F36 owner that has figured it out... don't bother explaining it to me... I've gone to option 2, and it took less time compared to everything I've done above.
Decided to do the U-Clip disconnect. 10 minutes total DIY, and no need to disconnect any harnesses. Easy to reconnect if I ever need to.
Here's a view of the clip in place from the other side of the exhaust:
Here's the clip (on my work towel :-)
...and the wire that keeps the flap in the open position:
