Physical boot-boundary trial — initcalls returned, login absent

2026-10-03 UTC. Branch integrate/mainline-probe-path, worktree /home/jadams/tmp/k230-mainline-probe-integration, bounded evidence base 174f8c164b870e5ecd9fa327eef202518fb25b20. Root reserved board/UART for this single trial; the controller closed serial and released its lock after failure. No build reservation remains.

The exact matching host-built bundle was staged with command RC0, its own GC root and the protected normal system retained. Actual ordinary-controller preparation passed before UART use. Controller preflight passed exact normal system/profile/kernel/init identities, 6.6.36, three active shell services, eight unchanged protected files and absence of a pending registration marker. Volatile U-Boot selection checked per-load byte counts and CRC32 plus exact printed bootargs before its one boot command. The option is k230.boot_trace=1, one serial console and the unchanged ordinary controller’s three qualified controls. No earlycon, keep_bootcon or global clock bypass was added.

python3 tools/mainline-drm-system-trial.py begin \
  --bundle /nix/store/cr8bv4s6gbchfmcm14c0hrl8agh7zn62-k230-mainline-drm-trial-boot-files \
  --manifest ~/tmp/k230-mainline-boot-trace-board/candidate-manifest.json \
  --normal-report ~/tmp/k230-mainline-boot-trace-board/normal-report.json \
  --state ~/tmp/k230-mainline-boot-trace-board/ordinary-trace-state.json \
  --log ~/tmp/k230-mainline-boot-trace-board/ordinary-trace-uart.log \
  --result ~/tmp/k230-mainline-boot-trace-board/ordinary-trace-result.json

Exit 1: ordinary init login readiness unverified. Fresh Linux 7.3.0-rc5 was observed, then these fixed allowlisted records:

[    0.018228] K230_BOOT_TRACE_V1 seq=1 step=basic-setup-enter
[    0.021599] K230_BOOT_TRACE_V1 seq=2 step=initcalls-enter
[    2.751970] clk: Disabling unused clocks
[    2.752146] PM: genpd: Disabling unused power domains
[    2.752212] K230_BOOT_TRACE_V1 seq=3 step=initcalls-exit

There were exactly three marker records. After the 180-second readiness bound there was no fresh login/root prompt, no basic-setup-exit and no init-exec record. Last UART bytes were received at 19:13:53.477346 UTC; the failed result was saved at 19:16:49.802410 UTC. The full raw log stays private; its SHA-256, byte count, exact artifact identities/CRCs and fixed-schema observations are in result.json. No candidate command or guessed reboot/retry was sent after readiness failed. The user subsequently pressed reset; protected normal recovery is verified in operator-reset-recovery.json. The new boot ID differs from preflight, normal system/profile/kernel/init and all eight boot files match exactly, all three shell services are active, and registration is absent. The bounded return-to-Home command completed with RC0; the privately reviewed camera frame shows normal Home icons, clock and background, with glare/focus/ perspective limits. This is normal recovery, not mainline or glass acceptance. Automatic return from this failed trial remains UNVERIFIED.

What this narrows, and what it does not prove

Exact realized source /nix/store/5k23sa4pbcs651vssp6ybifnr5qc1g9g-linux-mainline-k230-boot-trace-src/init/main.c has do_initcalls() at1486, its exit marker at1487, then returns at1488. kernel_init_freeable() calls do_basic_setup() at1711 and immediately emits basic-setup-exit at1712. There is no original blocking operation between these sites. The visible initcalls-exit proves the initcall loop reached its post-call marker; it does not prove that marker returned.

The helper’s lines1472–1475 include emergency enter, printk, emergency exit. Printk can flush consoles or defer/wake them; emergency exit may wake printing threads and re-enable preemption. The missing next marker can therefore lie in emission/flush, cleanup/scheduling or next-record visibility. This result localizes observed progress and does not establish a console deadlock, a stack, or a root cause. It does not show initramfs/root mounting stalled. The actual built configuration has KUnit disabled; the optional gap after basic setup is not a KUnit workload in this build.

The camera photograph was privately reviewed: the panel appears dark, with glare and perspective limits. That does not prove its power state or provide usable-mainline display/touch acceptance. Ordinary root, panel acceptance, deliberate glass touch, production controls and task5b.5 remain open.

Next bounded discrimination

After operator reset and protected normal postflight, inspect direct SBI DBCN public markers around the current marker return boundary. arch/riscv/include/asm/sbi.h and arch/riscv/kernel/sbi.c provide a direct call that bypasses printk/console locks; extension availability, buffer physical addressing, return/error handling and firmware-side blocking must be checked before implementation or another boot. Avoid the earlycon writer’s zero-progress retry loop. This is a candidate diagnostic plan, not an implemented fix or hardware claim.