RetroPie v4.8 Audio Fix for GPi CASE

config.txt

# For more options and information see
# http://www.raspberrypi.org/documentation/configuration/config-txt.md
# Some settings may impact device functionality. See link above for details

# uncomment if you get no picture on HDMI for a default "safe" mode
#hdmi_safe=1

# uncomment this if your display has a black border of unused pixels visible
# and your display can output without overscan
#disable_overscan=1

# uncomment the following to adjust overscan. Use positive numbers if console
# goes off screen, and negative if there is too much border
#overscan_left=16
#overscan_right=16
#overscan_top=16
#overscan_bottom=16

# uncomment to force a console size. By default it will be display's size minus
# overscan.
#framebuffer_width=1280
#framebuffer_height=720

# uncomment if hdmi display is not detected and composite is being output
#hdmi_force_hotplug=1

# uncomment to force a specific HDMI mode (this will force VGA)
#hdmi_group=1
#hdmi_mode=1

# uncomment to force a HDMI mode rather than DVI. This can make audio work in
# DMT (computer monitor) modes
#hdmi_drive=2

# uncomment to increase signal to HDMI, if you have interference, blanking, or
# no display
#config_hdmi_boost=4

# uncomment for composite PAL
#sdtv_mode=2

#uncomment to overclock the arm. 700 MHz is the default.
#arm_freq=800

# Uncomment some or all of these to enable the optional hardware interfaces
#dtparam=i2c_arm=on
#dtparam=i2s=on
#dtparam=spi=on

# Uncomment this to enable the lirc-rpi module
#dtoverlay=lirc-rpi

# Additional overlays and parameters are documented /boot/overlays/README

# Enable audio (loads snd_bcm2835)
dtparam=audio=on

#config_hdmi_boost=0

# force hdmi while the tv can take time before sending the signal on the hdmi output
#hdmi_force_hotplug=1

# uncomment for composite PAL
#sdtv_mode=2

# uncomment for lirc-rpi
#dtoverlay=lirc-rpi

# if you plug your tv at the same time as your rpi and that the rpi switches from the hdmi or give a low resolution because tv had no enough time to initialize it
boot_delay=3

# uncomment if you don't want the rainbow at startup
disable_splash=1

# default CEC name
cec_osd_name=recalbox

# Overclock
gpu_mem_256=128
gpu_mem_512=256
gpu_mem_1024=512

avoid_safe_mode=1

kernel=zImage

display_rotate=1
dtoverlay=dpi24
overscan_left=0
overscan_right=0
overscan_top=0
overscan_bottom=0
framebuffer_width=320
framebuffer_height=240
enable_dpi_lcd=1
display_default_lcd=1
dpi_group=2
dpi_mode=87
dpi_output_format=0x6016
#hdmi_timings=320 0 28 18 28 480 0 2 2 4 0 0 0 60 0 32000000 6
hdmi_timings=240 1 38 10 20 320 1 20 4 4 0 0 0 60 0 6400000 1

# Fixes RetroPie v4.8 audio for the GPi CASE
# See links below for sources/solutions
# https://retropie.org.uk/forum/topic/31555/no-sound-retroflag-gpi-case-with-pi-zero-w-2-solved/28
# https://www.reddit.com/r/retroflag_gpi/comments/kbd8jh/how_do_i_fix_failed_to_find_mixer_elements_if/

dtoverlay=audremap,pins_18_19,swap_lr