ILLEGAL INSTRUCTION | Invalid CPU instruction

What This Code Means

Where Users Usually See This Code

• Device status screens or logs
• During startup or initialization sequences
• While interacting with sensors, buses, or storage
• After firmware updates or configuration changes

Why This Code Appears

• A safety check or assertion failed
• The system restarted due to watchdog or power conditions
• A bus, peripheral, or storage operation failed
• A resource limit was reached (memory/stack)

What Typically Happens Next

• The device may reboot or enter a fault state
• A diagnostic message is logged
• Service intervention may be required for field equipment

What This Code Is Not

• It is not always user-repairable
• It is not safe to perform electrical repairs based on guesses

Troubleshooting Checklist

• □ Capture the full log output, including any stack trace or code
• □ Confirm firmware version and recent configuration changes
• □ Check power stability and environmental conditions
• □ Isolate peripherals and buses if the fault indicates I/O
• □ Use vendor diagnostics and service manuals for the exact model
• □ Escalate when the fault is recurring or safety-critical

Notes And Edge Cases