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E0204: backend execution failed

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What happened

The hardware backend’s execution path returned an error. The model loaded successfully, the input shape was valid, but the actual inference call failed.

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Why

This is a backend-specific error. Common causes:
  • The hardware driver is not installed or not running
  • The hardware device is not connected or not powered
  • The device ran out of neuron core resources for this model
  • A driver API call timed out or returned an unexpected status code

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How to fix

  1. Check the driver: ensure the hardware driver is installed and the device is connected. For Loihi 2: verify nxsdk is installed and lsusb shows the device.
  2. Check device resources: the model may require more neuron cores than are available. Try a smaller model.
  3. Check the error detail: the error message includes a backend-specific detail string from the driver. Use it to diagnose the hardware-level failure.
  4. Run on sim first: thrindex run model.thx --target sim to confirm the artifact is valid before debugging hardware.

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Example