Here is an overview to make sure it reconnects when using RetroPie 3.6
It didnt seem to reconnect for me in ES as it did for thak above. I had to use the method below. Assuming you are all on RetroPie 3.6
RetroPie help guides --> https://goo.gl/Yfy8kj
Please read this before asking for help --> http://goo.gl/eLErnl
Thx floob for your update!
I’m still with retropie 3.6 and rpi3 and my nes30pro connect automaticly if i turn it on at the end of the splashscreen (if not i’d just need to reboot the controller on émulationstation screen)
Since i found out this i’d never had anymore problem!