diff --git a/docs/re/BACKLOG.md b/docs/re/BACKLOG.md
index dfb0153..ce6e45d 100644
--- a/docs/re/BACKLOG.md
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@@ -6,6 +6,52 @@ unknown, what evidence exists, and what the first step would be. Move an item in
 
 ---
 
+## 🧰 The boot path — three failures that look like the emulator and are not (2026-08-26)
+
+* ✅ **`--audio` prevents boot outright.** `run-canary`'s own header says the flag
+  is not a cvar in this tree, and that an unknown argument makes xenia call
+  `ShowSimpleMessageBox` from `ParseLaunchArguments` *before* logging starts,
+  blocking forever. Measured anyway, because this corpus also holds runs that
+  passed it and booted fine: **3 trials each, in both orders** —
+
+  | | log written |
+  |---|---|
+  | `run-canary --apu=sdl --log_mask=13` | **67 565 bytes** |
+  | `run-canary --audio --apu=sdl --log_mask=13` | **209 bytes** |
+
+  209 bytes is `run-canary`'s own banner and not one line from xenia. The order
+  was reversed deliberately — this corpus already has a lesson that an A/B from
+  run order is noise.
+  🔴 **Eight scripts on branch `auto/idxd-unnamed-keys` still pass it**:
+  `launch_mission.sh`, `boot_menu.sh`, `fly_stage.sh`, `challenge_probe.sh`,
+  `grab_tutorial.sh`, `find_partslot.sh`, `tutorial_capture.sh`, `nav_probe.sh`.
+  `main` and this branch are clean, which reconciles August's successes with
+  today's failures. Left unfixed here: they are another branch's files.
+
+* 🔴 **`launch_mission.sh`'s `skip_intro` deadlocks on the attract loop.** It
+  classifies the screen as `movie` and declines to tap ("tapping breaks the
+  title"), and waited out **600 s of unbroken `movie` verdicts** before timing
+  out. `nav_to_flight.sh`, against the *same running emulator*, reached the main
+  menu in **12 s** and flight in **2 min 20 s** by tapping A at the title. The
+  "wait it out" premise is wrong — the attract loop does not end on its own.
+  **Use `nav_to_flight.sh` on an already-running canary.**
+
+* ⚠️ **`EMULATOR GONE at ~40 s` is this project's own Stop hook**, which
+  `kill -9`s every `xenia_canary` when a Claude turn ends. Already recorded
+  further down this file — and rediscovered the hard way over three boots because
+  I did not search for it first. The rule is the one `fly_session.sh`'s header
+  states: **an emulator session must be one task; nothing may depend on surviving
+  between tool calls.** Sequential tool calls *within* one turn are fine; it is
+  ending the turn that kills it.
+
+❔ **The world-unit measurement is still not made.** Flight was reached and the
+screen classifier agrees, but `entities2.py self` reports **0 unit definitions** —
+its committed VA window `0xBD00_0000`–`0xBE00_0000` does not match this run, the
+same run-dependent-address problem this file documents for the OB counter. The
+next attempt must hunt the range rather than trust the stored config.
+
+---
+
 ## ❌ WITHDRAWN (2026-08-26, same day) — the Japanese voice banks are NOT a separate format
 
 The `sound.pak` census (see