diff --git a/.asoundrc b/.asoundrc
index 4532266..3ca384f 100644
--- a/.asoundrc
+++ b/.asoundrc
@@ -1,9 +1,3 @@
-#pcm.!default {
-#        type hw
-#        card Zero
-##        card USB
-#}
-
 pcm.hw0mix {
     type dmix
     ipc_key 1939 # must be unique
diff --git a/README.md b/README.md
index 842cb98..4b74bd8 100644
--- a/README.md
+++ b/README.md
@@ -14,6 +14,11 @@ Hardware
 
 - USB speaker with a microphone e.g. [Jabra Speak 410](https://www.jabra.com/_/media/Jabra_VXi_Product-Documentation/Jabra-SPEAK-410-Series/technical-specifications/RevB/Jabra-Speak-410-Techsheet-A4-290420-Web.pdf) or [Codec Zero](https://www.raspberrypi.com/products/codec-zero/)
 
+- for the `Codec Zero` make follwoing changes
+> `sudo nano /boot/config.txt`  
+`#dtparam=audio=on`  
+`dtoverlay=rpi-codeczero`
+
 - microSD card 8GB
 
 - USB power supply 5V 500mA
@@ -22,7 +27,7 @@ Operating system
 ----------------
 Install [Raspberry Pi Imager](https://www.raspberrypi.com/news/raspberry-pi-imager-imaging-utility/) into your notebook. Launch it and choose `Raspberry Pi OS Lite` to write into the microSD card
 
-Power on the Raspberry pi and finish the installation process. Log into its console using either:
+Power on the `Raspberry Pi` and finish the installation process. Log into its console using either:
 - ethernet/wifi from your notebook: `ssh pi@raspberrypi`
 - connected keyboard and monitor
 - serial port
@@ -33,7 +38,7 @@ Once you are logged into the `Raspberry pi` console update your system
 > `sudo apt update`  
 `sudo apt upgrade`
 
-and install `git`. It will be used to download the `dog-trainer` 
+Install `git`. It will be used to download the `dog-trainer` 
 > `sudo apt install -y git`
 
 Recordings must be edited a little bit therefore some audio processing tool is needed. Install `ffmpeg` which will do the job  
@@ -52,14 +57,17 @@ Go into the newly created directory
 Configuration
 -------------
 
-First try using default audio device for playback and recording. Edit `dog-trainer.py` and activate `PLAY_DEVICE="default"` and `REC_DEVICE="default"`
+Check your Raspberry pi board pin layout and make sure your buttons GPIOs match `PINS = [17, 22, 27]` from `dog-trainer.py`
+> `pinout`
+
+Try using default audio device for playback and recording. Edit `dog-trainer.py` and activate `PLAY_DEVICE="default"` and `REC_DEVICE="default"`
 > `nano dog-trainer.py`
 
 Skip to the next section `Run it!`. If either playback or recording does not work check your sound cards
 > `aplay -L | grep ^hw:CARD=`  
 `arecord -L | grep ^hw:CARD=`
 
-Put your sound device name `card USB` or `card Zero` into ALSA config file
+Put your sound device name `"hw:Zero"` or `"hw:USB"` into the ALSA config file
 > `nano .asoundrc`
 
 Install the ALSA config file
@@ -83,8 +91,12 @@ If your username and group is other then `pi` and `pi` then also run
 > `sed -i "s#User=pi#User=$USER#" dog-trainer.service`  
 `sed -i "s#Group=pi#Group=$(id -gn)#" dog-trainer.service`
 
-Install the systemd service file
-> `sudo mv dog-trainer.service /etc/systemd/system/`
+> `sed -i "s#User=pi#User=$USER#" sound-init.service`  
+`sed -i "s#Group=pi#Group=$(id -gn)#" sound-init.service`
+
+Install the systemd service files
+> `sudo mv dog-trainer.service /etc/systemd/system/`  
+`sudo mv sound-init.service /etc/systemd/system/`
 
 Reload systemd manager configuration
 > `systemctl daemon-reload`
@@ -103,5 +115,5 @@ Launch soundcard mixer
 
 Press F6 to select a soundcard. Find your USB sound device in the list e.g. `Jabra Speak 410 USB`. Press F4 and use up/down arrow keys to set recording volume and repeat also for the playback (F3). Make sure it is not muted. Press (m) to toggle mute. Press ESC to exit.
 
-Make it survive after the restart
+To preserve audio setting after the boot run
 > `sudo alsactl store`
\ No newline at end of file