Symptom

You have a Home Assistant Yellow with a Compute Module 4 and the green LED flashes 4 times short and 5 times long.

Cause: firmware error

This LED pattern indicates a firmware error on the Compute Module 4 (CM4).

Resolution

To resolve this issue, you need to reinstall the Raspberry Pi bootloader onto the CM4.

To reinstall the Raspberry Pi EEPROM firmware on CM4

1. Open the procedure on re-installing the operating system on CM4.

2. Follow steps 1–7 of the section Option 2: Reinstall Home Assistant OS using rpiboot.

3. On Windows, open the Command Prompt window (cmd).

4. Run the following commands:

   cd \
   cd "Program Files (x86)"
   cd "Raspberry Pi"
   rpiboot.exe -d recovery
   

   Result: The green LED lights up solid, then starts flashing.

5. Wait for about 1 minute.

6. Then, from Home Assistant Yellow, unplug the power cable.

7. Ensure JP1 is set to UART.

8. On Home Assistant Yellow, connect the power cable.

   • Result: The error blink pattern should no longer occur.

     • The LED pattern depends on what is already installed on Yellow.

     • Typically, the system should boot now.

     • If Home Assistant OS is installed, the yellow LED should show a heartbeat pattern after ~5 seconds.

       

Related topics

• Re-installing the operating system on CM4