127s mash at 31250: zero wedges — but 5655 framing resyncs, duplicate
replies (215% of poll slots) and AbandonCount=65 reveal the board's
reply ACK-wait scales with byte time: ~5+ms at 9600 (USB beats it,
zero framing) vs ~1.6ms at 31250 (USB cannot). All 65 retry
exhaustions self-recovered through the patched give-up path — the
strongest field proof of the latch fix yet; unpatched firmware would
have wedged on the first. Verdict recorded in ANALYSIS.md: cabinets
run the 9600 patched chip; 31250 stays a bench branch until the retry
window is widened in firmware.
Tool: before-snapshot now retries once (can lose the post-DTR boot
race, as this run showed); evidence log archived.
Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>