Note: It is very unlikely that reinstalling the Home Assistant OS is necessary. Before going through this procedure, make sure to use the built-in device wipe mechanism.
To reinstall Home Assistant OS, the Home Assistant OS Installer for Yellow flashed on a USB flash drive needs to be used. However, the Raspberry Pi Compute Module 4 has a fixed boot order: eMMC -> NVMe SSD -> USB flash drive.
Option 1 disables booting of Home Assistant OS (from eMMC or NVMe SSD), which makes it possible to start the Installer again from a USB flash drive. This option only works if you currently have Home Assistant OS installed!
Option 1 (recommended): Reinstall Home Assistant OS using Red + Blue button
- Make sure no USB device is plugged into the device. Remove power from your system.
- Power up the system.
- Within 3s (or from start), press and hold the red and blue button on the backside of the device simultaneously.
- Hold the two buttons for approximately 10s. The Yellow LED should not start blinking!
- Remove power from your system.
- Follow the instructions to install Home Assistant OS using the Home Assistant OS Installer for Yellow from a USB flash drive.
Option 2: Reinstall Home Assistant OS using rpiboot
- Install rpiboot onto your computer.
- Open the Home Assistant Yellow enclosure to access jumpers on the PCB.
- Set JP1 to USB.
- Plug-in a USB-C cable to Home Assistant Yellow and connect it to your PC.
- Press and hold the USB-C Recvry push button. Older Home Assistant Yellow versions: Bridge JP2 (USB-C Rcvry).
- Power up the board. Only the red LED should be on at this point (solid, not blinking).
- Release the USB-C Recvry push button. Older Home Assistant Yellow versions: Un-bridge JP2.
- Run rpiboot on your PC and let it run through. Afterwards, the green LED should be on.
- Run the Raspberry Pi Imager and flash the Home Assistant OS Installer for Yellow onto the eMMC ("RPi-MSD"). Refer to Step 1 through 5 from the Installing Home Assistant Software on Kit procedure for the exact steps. Windows might bring up a message asking to insert a disk, this message can be closed. Ignore the Raspberry Pi Imager prompt to remove the SD card. Select Continue and close the Raspberry Pi Installer.
- Remove power from the board.
- Set JP1 to UART.
- Follow the instructions here. Note that because the installer is now installed to the eMMC, no USB flash drive is required.