To fix your problem, hard wire the escape key to “B2” connection. That will fix all your problems, there is no need to map the scape key in RetroArch/configs/all. Use the same key when you start the emulator, map the menu key as the scape key, in this way the key will do two things, it will pop up the menu and when you are into the game, it will exit, in this works in all the emulators. In my case MAME and Neo Geo are working perfectly. I cannot see why Super Nintendo and Genesis do not respond to the mapping key, it must be something in the software; let me know if you need any help or figure out anything.
Please let me know if you are available to get other emulators working with the ipac.
Take a look at my console in action!, let me know what you think!