Firmware & System Robustness
Detect and recover: watchdogs, plausibility checks, filtering in software, and the performance criteria that define pass/fail.
Hardware reduces the RF that reaches the victim; firmware handles what's left. Because RI failures often show as noisy or drifted readings rather than crashes, software plausibility and filtering can lift a design across the line — but only after the hardware has done its job.
Add communication integrity (CRC, retries) so RF-corrupted frames are re-sent, and refresh critical outputs periodically so a glitched register self-corrects. Design so any single upset degrades gracefully and recovers.
As with all immunity tests: A = normal throughout, B = self-recovering degradation, C = needs intervention. For RI, criterion B often means a sensor reading may wobble during exposure but returns to normal afterward — know which your product must meet.