install rasberry pi os
connect via ssh

edit /boot/firmware/config.txt
dtoverlay=hifiberry-dacplus-std
force_eeprom_read=0
auto_initramfs=1
disable_fw_kms_setup=1
disable_overscan=1
arm_boost=1
[cm4]
otg_mode=1
[cm5]
dtoverlay=dwc2,dr_mode=host

edit /boot/firmware/cmdline.txt
add ro to the end of the line

disable unused stuff
sudo systemctl disable bluetooth
sudo systemctl disable hciuart.service
sudo systemctl disable avahi-daemon.service
sudo systemctl disable triggerhappy.service
sudo systemctl disable dphys-swapfile.service
sudo systemctl disable apt-daily.timer
sudo systemctl disable apt-daily-upgrade.timer


setup user and group snapclient, add to audio group
sudo groupadd -r snapclient
sudo useradd -r -g snapclient -G audio snapclient
download snapclient release arm64 with pulse
wget https://github.com/badaix/snapcast/releases/download/v0.31.0/snapclient_0.31.0-1_armhf_bookworm_with-pulse.deb

install deb package
sudo dpkg -i snapclient_0.31.0-1_armhf_bookworm_with-pulse.deb
sudo apt install -f -y
vim.tiny /etc/default/snapclient
START_SNAPCLIENT=true
SNAPCLIENT_OPTS="--hostID music-bedroom -h snapcast.cloonar.com"

sudo systemctl enable snapclient
make filesystem read-only
mv /etc/resolv.conf /var/run/
ln -s /var/run/resolv.conf /etc/resolv.conf
add /etc/NetworkManager/NetworkManager.conf main
rc-manager=file

change /etc/fstab
proc            /proc           proc    defaults          0       0
PARTUUID=3bd31f85-01  /boot/firmware  vfat    defaults,ro          0       2
PARTUUID=3bd31f85-02  /               ext4    defaults,noatime,ro  0       1

tmpfs /tmp tmpfs defaults,noatime,nosuid,nodev 0 0
tmpfs /var/tmp tmpfs defaults,noatime,nosuid,nodev 0 0
tmpfs /var/log tmpfs defaults,noatime,nosuid,nodev,noexec 0 0
tmpfs /var/lib/dhcp tmpfs defaults,noatime,nosuid,nodev,noexec 0 0