Teams often parallelize board bring-up and driver landing at the same time. Without a ledger, regressions hide inside overlapping commits. We snapshot reset-to-frame milestones first so every later change has a reference plane.
The ledger is not a vanity metric. It pairs timestamps with power-state transitions, flash wait states, and peripheral clock enables. When a regression appears, you can bisect against a narrow window instead of replaying an entire sprint.
We recommend keeping the ledger in CI with a smoke profile that is slower than unit tests but faster than full system validation. That balance keeps the signal honest without starving throughput.
Finally, document what you refuse to optimize. Some third-party blobs resist introspection; naming those boundaries prevents thrash between hardware and firmware owners.