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    OTA / patch mechanism audit

    OTA Update Questionnaire

    Score the patch / OTA update mechanism your device ships with against integrity, transport, deployment safety, lifecycle, and - for AI/ML devices - PCCP-bound model update and rollback expectations under §524B and the FDA's Feb 3, 2026 final premarket cybersecurity guidance.

    Christian Espinosa, Founder & CEO, Blue Goat Cyber

    Reviewed by

    Christian Espinosa

    Founder & CEO, Blue Goat Cyber

    Last reviewed June 29, 2026

    Update Integrity & Authenticity

    What stops a malicious or corrupted update from reaching the device.

    Update images are signed with a manufacturer-controlled key

    critical

    Asymmetric signature, not just a checksum.

    Device verifies signature before applying any update

    critical

    Bootloader / OS verifies before commit.

    Signing chain anchored in hardware or measured boot

    high

    Root key in HSM / secure element / TPM.

    Signing keys live in an HSM with documented access controls

    high

    No keys on engineer laptops.

    Update Transport & Distribution

    How updates get from your build system to the device.

    Update server uses mutual TLS or pinned certificates

    high

    Server authenticates the device and vice versa.

    Rollback protection (anti-downgrade) is enforced

    high

    Monotonic version counter checked at boot.

    Delta or differential updates use the same signing + verification path

    medium

    Deltas are a common bypass.

    Update Deployment & Safety

    How updates get applied without harming patients.

    A/B (dual-bank) update with automatic rollback on boot failure

    critical

    Device never bricks on a bad update.

    Update preconditions checked (not in clinical use, battery, network)

    high

    No updates mid-procedure.

    Operator / customer notification and consent workflow exists

    medium

    Per labeling requirements.

    Staged / canary rollout supported

    medium

    Catch field-only issues before fleet-wide.

    Lifecycle & Reporting

    Postmarket controls reviewers expect under §524B.

    Documented SLAs for critical / KEV-relevant patch deployment

    high

    Aligned to Postmarket Cadence Calculator output.

    Per-device update success / failure telemetry collected

    high

    You can prove fleet status to reviewers.

    Audit log of every update (who, what, when, version, signature)

    medium

    Tamper-evident.

    Key compromise / revocation playbook exists and has been rehearsed

    high

    Including emergency re-signing.

    Cyber update support window stated in labeling (with EoS date)

    medium

    Per §524B and FDA premarket guidance.

    AI / PCCP Model Updates

    For AI/ML-enabled devices: how model weight updates ship, stay bound to the authorized PCCP envelope, and roll back safely. Skip this group only if the device ships no learned model.

    Model weights ship over a separate, identified update channel (distinct from firmware / OS)

    high

    Reviewers want to see model artifacts treated as a first-class update class, not bundled silently with firmware.

    Model artifacts (weights + preprocessing + thresholds) are signed and verified before load

    critical

    Cover the full inference bundle, not just the .pt / .onnx file.

    Each model update is checked against the authorized PCCP envelope on-device before activation

    critical

    Architecture family, input modality, intended use, performance floors, and population are all inside the cleared modification protocol.

    Model manifest cryptographically binds weights hash to the PCCP submission ID and protocol version

    high

    So a model can be traced back to the exact PCCP version the FDA cleared.

    Out-of-envelope model changes are blocked at deploy time and require a new submission path

    critical

    No silent re-architecture under the same clearance.

    Previous validated model version is retained on-device and can be reactivated automatically

    critical

    A/B for model weights, not just firmware.

    Model rollback is bounded by a known-good allow-list (no downgrade to vulnerable / withdrawn weights)

    high

    Anti-downgrade for models, with an explicit exception for safety rollback.

    Post-update real-world performance monitoring gates the rollout and can trigger automatic rollback

    high

    Drift, subgroup performance, and confidence calibration tracked per release.

    Per-device log records active model version, manifest hash, PCCP version, and activation time

    medium

    Tamper-evident provenance for postmarket investigations.

    What you'll see after you submit

    OTA mechanism scored across signing, transport, deployment, and lifecycle

    • Per-item severity rating (Critical / High / Medium) tied to reviewer expectations.
    • Gap list grouped by severity with a concrete remediation per item.
    • Weighted maturity score that down-weights cosmetic items and up-weights signing + rollback safety.
    • JSON export for handing to firmware, cloud, and DevOps owners.

    Common misconceptions

    What teams usually get wrong

    • Myth: TLS to the update server is enough.

      Reality: TLS protects the channel. The FDA expects signature verification of the image itself, plus rollback protection - bytes on the device must be authenticated, not just the transport.

    • Myth: We don't need A/B partitions because we test thoroughly.

      Reality: Field environments differ from labs. Without dual-bank + watchdog rollback, one bad release can brick a fleet and turn a security update into a recall.

    • Myth: Signing keys can live on the build server.

      Reality: Keys on a build server are one CI compromise away from being used to push a malicious update at scale. HSM / KMS with dual-control is the bar reviewers expect.

    Why this tool is current

    Recent regulatory + supply-chain activity

    Tracked signals that change what reviewers expect. Items move on as new ones land.

    Pair with