A computing device includes a processor, firmware, a hardware component, and a debugging module. The firmware stores error decoding logic particular to the computing device. The hardware component detects an error in the computing device, and responsively issues an interrupt and halts the processor such that the processor cannot execute any more computer-readable code. The debugging module loads the logic from the firmware at reset and executes the logic responsive to the interrupt. The debugging module does not use the processor to execute the logic, the firmware is not part of the debugging module, and the debugging module is not part of the hardware component. The firmware may also store a mapping between registers of the hardware component and field-replaceable hardware units of the computing device, which the debugging module loads at reset and uses when executing the error decoding logic to determine which unit has caused the error.