Problem is that some games does not work with the multitap on, Like Tetris and Dr. Mario. I found the pull request #770 that solves my problem, but could not find the menu that creates the custom cfg file. https://github.com/RetroPie/RetroPie-Setup/pull/770
1. Copy the /opt/retropie/configs/snes/retroarch.cfg to the snes roms directory with the same name of the ‘%.smc’ file, excluding the ‘input_libretro_device_p2 = “257”’ line.
2. Same thing with the /opt/retropie/configs/all/retroarch.cfg file