Fixing sound on RetroPie after updating and installing Desktop Environment

I started out by imaging retropie-buster-4.7.1-rpi2_3.img.gz onto an SD card for a Raspberry Pi 3 B. Then I updated the software using the menus in EmulationStation. Then I installed the desktop environment, again with the ES menus. What resulted was audio no longer working in EmulationStation and the console emulators. I did a whole bunch of things to troubleshoot, so I'm not sure what actually made it work.

/boot/config:

hdmi_drive=2
hdmi_force_hotplug=1
hdmi_force_edid_audio=1

Install:

sudo apt install pavucontrol pulseaudio-utils
sudo apt-get install lxplug-volumepulse

In the desktop environment, add Volume Control panel to the menu bar.

In EmulationStation, Audio Card: hw, Audio Device: HDMI.

Troubleshooting

Play audio with Alsa:

sudo aplay /usr/share/sounds/alsa/Front_Center.wav

Speaker test:

speaker-test -D sysdefault -t wav

Fix init sequence in Raspberry Pi

If the init sequence gets broken and you can't get to a shell on a Raspberry Pi (I'm using 3 model B), you can boot into recovery mode this way.

• Hit shift when starting up.
• Hit "e" to edit config
• tab over to cmdline.txt
• add to the end of the line
  init=/bin/sh
• hit ok, then Esc to boot...... it will boot you in to a command line
  # mount -n -o remount,rw / (this will remount / so you can make changes)
• now you should be able to edit the init.d config.
• when you reboot again.... hold shift and remove the init=/bin/sh

Source: raspberrypi.stackexchange.com