diff --git a/rio-firmware/RIOv4_2-ANALYSIS.md b/rio-firmware/RIOv4_2-ANALYSIS.md
index 5d06d8f..14b1943 100644
--- a/rio-firmware/RIOv4_2-ANALYSIS.md
+++ b/rio-firmware/RIOv4_2-ANALYSIS.md
@@ -531,8 +531,18 @@ first counter event — `04000000` flashes momentarily, then `E000000x`
 as errors accrue and the reply-latch wedge trips under load. The wedge
 fix plus the E0 threshold gate are what exposed the stale frame.
 
-**RC1 first-light (burned 2026-07-19): PASS on the below-threshold
-path** — a version+check exchange now leaves the display at `F0000000`.
-Remaining for the RIO 4.3 christening: over-threshold check repaint
-(must re-render the E0 readout), `--e0test` regression, mash
+**RC1 acceptance (burned 2026-07-19): PASS on both edit-6 paths.**
+Below threshold: a version+check exchange leaves the display at
+`F0000000`. Over threshold: the full `--e0test` sequence reproduced the
+certified behavior (held `F0000000` through four sub-threshold events,
+flipped at the 5th teardown), and the closing CheckRequest — 65 status
+frames — left the display at **`E0000305`**: repaint + live E0
+re-render, not the stale `04000000`. The `$3184`=03 (vs predicted 01)
+pins down the counter semantics one notch further: two of the 65 check
+frames hit a timeout-retry that our late ACK then rescued — so
+**`$3184` counts started timeout-retry sequences** (give-ups are the
+subset that exhaust all 5 retransmits), and a timeout-recovered cycle
+exits via the success teardown (no `$3185`), while NAK-recovered cycles
+tear down through `$DA2F` (`$3185`). Every observation from both bench
+sessions fits this model. Remaining for the RIO 4.3 christening: mash
 spot-check.
diff --git a/tools/RioSerialMonitor/E0Test.cs b/tools/RioSerialMonitor/E0Test.cs
index c9d7945..49be8bf 100644
--- a/tools/RioSerialMonitor/E0Test.cs
+++ b/tools/RioSerialMonitor/E0Test.cs
@@ -218,8 +218,9 @@ internal static class E0Test
             int checkReplies = Count(chk, 0x85);
             Console.WriteLine($"[check  ] CheckRequest sent: self-test ran (lamps flash), {checkReplies} status frame(s).");
             Console.WriteLine($"          Edit-6 chips repaint, then re-render the over-threshold E0 readout.");
-            Console.WriteLine($"          >>> DISPLAY SHOULD NOW READ: {Expected(cycles, teardowns)} (may run one higher in the last pair;");
-            Console.WriteLine($"              04000000 here = no edit 6 on this chip) <<<");
+            Console.WriteLine($"          >>> DISPLAY SHOULD NOW READ: {Expected(cycles, teardowns)} — small drift in either pair is normal");
+            Console.WriteLine($"              (late ACKs among the status frames start timeout retries: $3184 +1 each;");
+            Console.WriteLine($"               04000000 here = no edit 6 on this chip) <<<");
             await Task.Delay(3000);
         }