Home Assistant Raspberry Pi CM4 – installation guide

In my previous discussion I wanted to install Home Assistant on Raspberry pi cm4 module. Due to supply shortage I was not able to do the installation. But this changed recently now I have a CM4 model to test.

Installing CM4 module

Hardware selection

I have picked a Raspberry pi compute module (cm4) that has the following

  • Internal storage (16GB eMMC)
    I want to use the eMMC storage over microSD card. This will give Home Assistant quick access to data and long life over any microSD card.
  • 2GB RAM
    Good enough for my project
  • No WiFi
    Home Assistant recommend ethernet over WiFi

PiTray min from Sourcekit

This is one of the chipper option from all available board. I have picked this for ethernet port and eMMC boot options

Setup Hardware

Very simple setup just all CM4 to PiTray min.

Home Assistant setup

Step 1: Setting up my mac (Or PC), install and launch raspberry pi usbboot.


From a macOS machine, you can also run usbboot, just follow the same steps:

  1. Clone the usbboot repository
  2. Install libusb (brew install libusb)
  3. Install pkg-config (brew install pkg-config)
  4. Build using make
  5. Run the binary
git clone --depth=1 https://github.com/raspberrypi/usbboot
cd usbboot
brew install libusb
brew install pkg-config
sudo ./rpiboot


  • Download latest Home Assistant iso from GitHub (Latest download links)

Note: for some reason Balena Etcher download from URL option did not work for me as a result I have download the .img file manually

CM4 with eMMC (Flashing Guide)

  1. Power Off. Unplug micro SD card from PiTray (if any).
  2. Mount the CM4 (with eMMC) on PiTray. 
    CAUTION: be careful of the CM4 position, align the CM4 layout corner marks and holes, otherwise CM4 or PiTray would get damaged
  3. Make sure the eMMC Boot switch is at the OFF position.
  4. On PC/Mac, launch usbboot
    > sudo ./rpiboot
  5. Connect PiTray mini with a USB-A to USB-C cable to the PC.
    (Note: USB-C to USB-C does not work for me)
  6. Then an external disk like flash drive, aka USB mass storage, would show up on the PC/Mac, write this disk with OS image with Raspberry Pi Imager or Etcher.
  7. After the image is written and the external drive is umounted from PC, disconnect PiTray mini from the PC.
  8. Power PiTray with a 15W USB-C power supply. With the red led on, you are good to go. Enjoy & have fun.
  • For CM4 with eMMC that already filled with OS image, just start from Step 8 for regular usage.

Start up

  1. Turn the eMMC Boot switch to ON.
  2. Attach a ethernet cable for network.
  3. Power PiTray with a 15W USB-C power supply.
    CAUTION: Use a good power supply I used Raspberry official power supply. My initial test with mobile usb-c charger did not work.
  4. Within a few minutes you will be able to reach Home Assistant on homeassistant.local:8123. If you are running an older Windows version or have a stricter network configuration, you might need to access Home Assistant at homeassistant:8123 or http://X.X.X.X:8123 (replace X.X.X.X with your Raspberry Pi’s IP address).

Enabling USB

CM4 by default USB is disabled. I did the following to update the configuration

  • Go inside the usbboot folder > recovery
sudo nano  recovery/config.txt
  • Add the following line
  • run pieeprom.sh command
sudo ./update-pieeprom.sh
+ /usbboot/tools/rpi-eeprom-config --config boot.conf --out pieeprom.bin pieeprom.original.bin
+ set +x
new-image: pieeprom.bin
source-image: pieeprom.original.bin
config: boot.conf
  • Update the bootloader and connect the CM4 (eMMC button Off) to my laptop
sudo  ./rpiboot -d recovery
RPIBOOT: build-date Jan 26 2022 version 20220111~130126 9064cd86
Loading: recovery/bootcode4.bin
Waiting for BCM2835/6/7/2711...
Loading: recovery/bootcode4.bin
Sending bootcode.bin
Successful read 4 bytes 
Waiting for BCM2835/6/7/2711...
Loading: recovery/bootcode4.bin
Second stage boot server
Loading: recovery/config.txt
File read: config.txt
Loading: recovery/pieeprom.bin
Loading: recovery/pieeprom.bin
Loading: recovery/pieeprom.sig
File read: pieeprom.sig
Loading: recovery/pieeprom.bin
File read: pieeprom.bin
Second stage boot server done

Note: for some reason USB did not mount. So I have completed the following steps

diskutil list
/dev/disk2 (external, physical):
   #:                       TYPE NAME                    SIZE       IDENTIFIER
   0:      GUID_partition_scheme                        *15.6 GB    disk2
   1:         Microsoft Reserved ⁨⁩                        33.6 MB    disk2s1
   2:           Linux Filesystem ⁨⁩                        25.2 MB    disk2s2
   3:           Linux Filesystem ⁨⁩                        268.4 MB   disk2s3
   4:           Linux Filesystem ⁨⁩                        25.2 MB    disk2s4
   5:           Linux Filesystem ⁨⁩                        268.4 MB   disk2s5
   6:           Linux Filesystem ⁨⁩                        8.4 MB     disk2s6
   7:           Linux Filesystem ⁨⁩                        100.7 MB   disk2s7
   8:           Linux Filesystem ⁨⁩                        14.9 GB    disk2s8

Created a temporary folder and mount the disk2s1 (Microsoft Reserved) to that folder

mkdir /user/drive
# Create area to mount FAT partition 
mount -t msdos /dev/disk2s1 /user/drive
diskutil mount /dev/disk1s2

Now open the config.txt in text editor add the following lines



Testing USB in hass.io

Insert the USB device into the USB port

Configuration > System >Host
click on (...) dropdown > hardware 

And your device should be listed under USB