diff --git a/docs/panels.md b/docs/panels.md
index d9c47f7..ea878cd 100644
--- a/docs/panels.md
+++ b/docs/panels.md
@@ -168,6 +168,21 @@ selection while wearing the headset, physical placement, and non-XR Chromium.
 The API reports that focus was *requested*: another action can take focus before
 we observe the result. Closed panels are rejected after re-enumeration.
 
+### Shared-device recheck, 2026-09-29
+
+**Verified:** the follow-up's atomic `mkdir /tmp/frame-test.lock` attempts
+failed because another thread held the lock. The existing lock was left alone;
+no applications were installed, launched or stopped in this follow-up. The last
+read-only battery check showed 62%, charging. The 180 Python and 8 website tests
+passed again locally.
+
+**Unverified in this follow-up:** the prepared browser-button test (Refresh,
+selection, reload and Close) and repeated OpenXR transition could not run under
+the shared lock. The device results elsewhere in this page are the earlier
+2026-09-28 observations, not results from this blocked recheck. In particular,
+HTTP focus is not evidence of worn-headset laser input. Follow the
+[shared-device test procedure](testing.md#headset-smoke-test) for the next run.
+
 ## Saved spatial layouts: blocked on the current panel route
 
 **Verified 2026-09-28**, same build, using a temporary xterm panel with
diff --git a/docs/testing.md b/docs/testing.md
index a36b7b7..2e85f51 100644
--- a/docs/testing.md
+++ b/docs/testing.md
@@ -104,6 +104,20 @@ switch while SSH is down:
 
 ## Headset smoke test
 
+**Documented shared-device procedure:** before a test installs, launches or
+stops an application, acquire `ssh frame 'mkdir /tmp/frame-test.lock'`. If it
+fails, leave that lock alone and continue offline work. Only the thread that
+acquired it releases it with `ssh frame 'rmdir /tmp/frame-test.lock'`, after
+cleanup. Keep each device session to a few minutes.
+
+Check battery capacity and charging state under `/sys/class/power_supply`
+before and after; keep capacity above 20%. Stop only processes started by the
+test, remove temporary installs and profiles, and restore the prior dashboard
+state. Leave Steam and SteamVR running. Do not reboot or change global settings.
+Record the build, actual interaction results, cleanup and any unworn-headset
+limits alongside screenshots or logs. These are caller responsibilities; the
+smoke script below does not acquire this shared lock itself.
+
 ```sh
 scripts/frame-smoke.sh           # needs `ssh frame` to work without a password
 scripts/frame-smoke.sh --pair    # also pairs a throwaway key: approve it in the headset