diff --git a/docs/PERFORMANCE.md b/docs/PERFORMANCE.md
index 32c138c..b39a98b 100644
--- a/docs/PERFORMANCE.md
+++ b/docs/PERFORMANCE.md
@@ -90,18 +90,28 @@ The workflow:
 ```
 
 **The Gradle runner is required, not preferred.** Macrobenchmark's rule uninstalls the app at the start
-of a run and reinstalls it before measuring. On this device *that reinstall* is what MIUI refuses, so the
-run leaves the app uninstalled and then fails with `NameNotFoundException` for an app that was there a
-second earlier — seen twice through `am instrument` and once through `connectedDebugAndroidTest`, with
-`Benchmark: Uninstalling de.softwareapp_hb.filemanager` in logcat and the package gone from
-`pm list packages` afterwards.
+of a run and reinstalls it before measuring. That alone is survivable; what is not is the side effect:
+**an uninstall clears the app's app-ops**, so the `MANAGE_EXTERNAL_STORAGE` grant from
+`tools/benchmark-fixture.sh` is gone by the time the test navigates. The app then correctly shows its
+"choose a folder" fallback, the volume row is not on the screen, and the assertion says so. Checked
+directly — `appops get … MANAGE_EXTERNAL_STORAGE` reads `No operations` after a run that passed through
+the reinstall.
 
-The fix is a device setting rather than code: *Developer options → Install via USB* — and on MIUI usually
-*MIUI optimization off* as well — so that an install raised by the benchmark is allowed without a prompt.
-Until that is on, **the interaction benchmarks cannot run on this phone**, and the cold-start number above
-stands alone. `tools/benchmark-fixture.sh` is still needed either way: the benchmark build has no storage
-grant of its own, and `UiAutomation.executeShellCommand` (the only shell a test has) runs with the test
-app's uid and cannot write `/sdcard`.
+There is no way around that from inside the test: granting an app-op needs the shell's uid, and
+`UiAutomation.executeShellCommand` runs with the *test app's* uid. So on a device where this app needs
+that grant — which is every device, for the browser screen — **the three interaction benchmarks cannot run
+as macrobenchmark tests here**, and the cold-start number above stands alone.
+
+Two paths would give the numbers, and neither is a small change:
+
+- **A plain instrumented test instead of a macrobenchmark one** (no rule, so no reinstall): install the
+  benchmark build once, grant, then navigate with UiAutomator and read frame durations from
+  `FrameMetrics`. It measures the release-like build, but it is our own measurement code rather than a
+  maintained library, and `FrameTimingMetric` exists precisely so nobody has to write that.
+- **An app that does not need the grant for the flow being measured** — for instance a benchmark
+  build that browses its own external files directory, which needs no permission. That measures a
+  different screen than the one users open, so it answers a narrower question than "how fast does
+  opening a 1 000-file folder feel".
 
 ## Not measured yet, and why