I followed your very useful video and decided to try it on the Megadrive one, all works, but again if I hit my button 8 whilst playing a game it won’t quit back to the emulationstaion screen. This is my retroarch.cfg for the Megadrive:

# Settings made here will only override settings in the global retroarch.cfg if placed above the #include line

input_remapping_directory = /opt/retropie/configs/megadrive/
# video_smooth = false
video_shader = /opt/retropie/emulators/retroarch/shader/phosphor.glslp
# video_shader_enable = true

video_aspect_ratio_auto = “false”
video_fullscreen = “true”
aspect_ratio_index = “10”
input_player1_select_btn = “7”
input_player1_start_btn = “6”
input_player2_select_btn = “7”
input_player2_start_btn = “6”
input_exit_emulator = “8”
input_exit_emulator_btn = “8”

#include “/opt/retropie/configs/all/retroarch.cfg”