Rebuilt with KBUILD_BUILD_USER/HOST/TIMESTAMP pinned. Without them the kernel
bakes the builder's user@hostname and wall-clock build time into /proc/version,
which publishes operator identity in a public artifact and makes the build
unreproducible. Pinned, anyone can rebuild and diff the bytes — the only trust
story available for an unsigned community kernel.
The installer refuses to run on anything but a Pi 4, refuses a mismatched
image/modules pair (vermagic failure means no /dev/pps0 on a kernel that
otherwise boots fine — silent and miserable to debug), verifies SHA256SUMS,
never touches kernel8.img, and leaves rollback as deleting one config.txt line.
Boot-tested on the Pi: Stratum 1, 273 ns offset, PPS handler confirmed NOT
threaded. Binaries ship as release assets, not in git.
What the Raspberry Pi time-server guides get wrong on a Pi 4, with the
measurements. The headline artifact is a four-line pps-gpio patch: PREEMPT_RT
force-threads IRQ handlers, and pps-gpio takes its timestamp inside its handler,
so the realtime kernel puts a scheduler between the electrical edge and the
clock. IRQF_NO_THREAD takes RMS offset from 2468 ns to 199 ns.
- kernel/ the patch
- dashboard/ live status page (position hidden by default)
- docs-site/ the write-up (Astro/Starlight, brass, no tutorial section)
