While connected to the RC via wifi to my iphone 6, I tried the RTH button on the RC and it did not activate. I had also set up my customizable button to toggle the gimbal straight forward/down and it did not work. I made sure I was out of sports mode when doing this. I got the Spark a couple of months back and that button did work but now it did not. I had not tried the RTH button before so I am not sure if it did work at some point. Has anyone else had this problem with their buttons not working on the RC?

WiFi or with OTG cable.  I have had issues with the buttons when using OTG

On RC you need  to hold the RTH button for about 2-3 sec for it to initiate command to SPARK

Agree with SeanGillian. have you tried to press and hold the RTH button for several seconds to initiate the RTH? Besides, for the customizable button issue, please double check the settings on the APP, if it is the same, please post a short video about it for better assistance.

I have tried it with both the OTG cable and without it. I have not tried holding the RTH button for 2-3 seconds. I will try that once I get out to fly it later. I will go ahead and try to test the customizable button issue and record it. Thanks for the assistance everyone.