Note: It is very unlikely that this is necessary. Before going through this step, make sure to use the built-in device wipe mechanism.
By default the Raspberry Pi Compute Module 4 has a fixed boot order which tries to boot from the internal eMMC before booting from a USB mass storage device. In rare cases it can be that the internal eMMC is deemed bootable, but does not boot into a working system. In this case, there are two options you can try to reinstall Home Assistant OS.
Option 1 (recommended): Reinstall Home Assistant OS using Red + Blue button
This option works with Home Assistant OS 8.5 and later only.
- Remove power from your system
- Power up the system
- Within 5s (or from start), press and hold the red and blue button on the backside of the device simultaneously.
- Hold the two buttons until only the red LED is lit.
- Remove power from your system
- Follow the instructions to install Home Assistant OS using the Home Assistant OS Installer from a USB flash drive.
Option 2: Reinstall Home Assistant OS using rpiboot
- Open Home Assistant Yellow enclosure to access jumpers on the PCB.
- Set JP1 to USB.
- Bridge JP2 (USB-C Rcvry).
- Plug-in a USB-C cable to Home Assistant Yellow and connect it to your PC.
- Power up the board. Only the red LED should be on at this point (solid, not blinking).
- Run rpiboot on your PC and let it run through. Afterwards, the green LED should be on.
- Run 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 an message asking to insert a disk, this message can be closed. The Raspberry Pi Imager prompt to remove the SD card can be ignored as well. Press Continue and close the Raspberry Pi Installer.
- Remove power from the board.
- Un-bridge JP2.
- 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.
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