Problem solve........

No need to chance any software.
Here how it work with Spektrum set up.

After you finish ATV adjust your retract system.
Binding your reciever again with gear up postion.
Now turn it off and hook up the retract servo to the gear failsafe. Turn on Tx and Rx to start the program sequence as instruction showing you.

After you got everything done.

To test the gear fails safe. Turn on your TX with gear up position and turn your RX.
The gear failsafe should be in the failsafe mode not allowing gear to go up.
Once you put your gear swicth in down position. That will disable failsafe mode.
Give it a try.