Board-level Linux integration, U-Boot, device trees, kernel drivers and peripheral bring-up. Separate power and hardware checks from software adaptation, and define a recoverable boot path.
Report the failing stage together with the observed cause and raw result. A boot error code alone may merge flash-read, format, hash and signature failures. Support can act on a precise refusal reason without weakening the refusal itself. This guide pins U-Boot v2024.10’s simple-SPL FIT path and its verification helpers. The proposed public reason labels…
A signature result remains useful only while the bytes and policy inputs it covers stay unchanged through their use. When a peripheral can write relevant RAM, the boot review needs a memory-ownership timeline covering the verification interval and handoff. A successful hash at one instant does not establish that timeline. This is a platform qualification…
Trace a signed FIT configuration through its image hash to the exact external bytes the loader reads. External storage does not inherently remove authentication, but a configuration signature alone is not a whole-file checksum or proof that every location field is authenticated. This guide pins U-Boot v2024.10. Its main address worksheet follows the memory-resident FIT…
Predict FIT best-match selection from the ordered compatibility list in U-Boot’s control device tree, then check equal-priority ties and explicit selectors separately. A chosen configuration is a selection result. It still needs the product’s authentication and board-qualification evidence before use. This guide pins U-Boot v2024.10’s fit_conf_find_compat() and its fit_image_load() caller. It does not assert that…
A hash comparison authenticates firmware only when the expected hash comes from an independently trusted source. If an adversary can replace both a FIT payload and its stored digest, a correct digest calculation can still accept the substituted pair. The algorithm may be working exactly as implemented while the product’s authenticity claim is unsupported. This…
Audit SPL as its own verifier binary. A main U-Boot build that supports FIT signatures does not establish that SPL authenticates the next image before executing it. The useful evidence is a chain from resolved SPL configuration through linked code and consumed key policy to an observed SPL rejection. This procedure pins U-Boot v2024.10 and…
Audit the final boot-policy inputs, not only the signature on the executable image. A correctly verified kernel can receive command-line arguments assembled from a separate mutable source. If those arguments choose storage, initial userspace or security-relevant behavior, their authority belongs in the boot trust review. This guide uses U-Boot v2024.10’s common Linux device-tree setup and…
Trace the actual loader caller before relying on a FIT image’s phase property. The property is selection metadata, not a universal rule that every SPL or VPL path applies automatically. A correctly labelled image can remain unused, and an unlabelled image can be selected first. This article pins U-Boot v2024.10. It compares the generic fit_image_load()…
Authenticate the selected FIT configuration and its required image hashes when the approved unit is a kernel/device-tree combination. Individually signed components can establish who signed each component while leaving the relationship between them unprotected. A release review must therefore ask both “are these bytes approved?” and “is this combination approved?” This guide pins U-Boot v2024.10…
Read Linux suspend statistics before and after one controlled attempt, then correlate changed phase counters with callback logs. Historical last-failure fields are clues, not a fresh, atomic failure record. A recent wake event does not explain a failure that actually occurred while freezing tasks, preparing a device, or restoring it during unwind. Applicability: this article…