e0t5 mash regression: PASS (0 wedges, counters flat) + live test-mode incident

120s lamps-on mash on the burned 9600 e0t5 chip: 236/236 presses, 88.0%
analog fill, NAK 0, zero wedges, board counters flat — normal operation
unaffected by the E0-threshold patch. Bonus field data: the keypad
A-9-E chord fired mid-mash and dropped the board into axis test 4
(display 04000000), confirming that button scanning halts in test mode
while ISR-driven serial keeps running — visible in the log as presses
freezing at 236 while analog continued to 1919.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

RIOv4_2-ANALYSIS.md

@@ -497,6 +497,14 @@ cycle): the display held `F0000000` through the handshake and all four
 sub-threshold teardowns — stock paints `E0…` at the first — and flipped
 exactly at the 5th teardown to **`E0000105`** (`$3187`=00 overflows,
 `$3184`=01 give-up, `$3185`=05 teardowns), confirmed by eye on the
-cockpit display. Mash regression still to run. The 31250v2_e0t5 image
+cockpit display. Mash regression (120s, lamps on,
+`testlogs/riomash-patched-e0t5-9600-20260719-154259.log`): **PASS** —
+0 wedges, 236/236 presses, 88.0% analog fill, NAK 0, board counters
+flat. Incidental live finding: mid-mash the cockpit keypad delivered
+the A-9-E test-mode chord plus a `4`, dropping the board into axis
+test 4 (display `04000000`) — button scanning stops in test mode
+(mainline parks in the test loop) while the ISR-driven serial protocol
+keeps answering polls. Field-validates the display doc's test-mode map;
+exit is keypad `F` then `D`. The 31250v2_e0t5 image
 is the same patch on the certified FastRIO base and is expected to
 behave identically.

testlogs/riomash-patched-e0t5-9600-20260719-154259.log

@@ -0,0 +1,28 @@
+== RIO mash test :: COM1 @ 9600 8N1, 120s, chip label 'patched-e0t5-9600' ==
+   lamp echo ON (drives reply/lamp collisions), wedge threshold 2.0s, poll 55ms, app auto-recovery DISABLED
+   log: c:\VWE\riojoy\riomash-patched-e0t5-9600-20260719-154259.log
+   firmware: 4.2
+   counters before: RestartCount=0  AbandonCount=0  FullBufferCount=0  [board/lamp faults reported!]
+
+>>> MASH NOW: two hands, 8 lamp buttons, as fast as you can. <<<
+>>> Test runs 120s. A wedge alarm will beep + banner.   <<<
+>>> Ctrl+C ends the run early and still prints the summary.   <<<
+
+[  31.88s] progress: presses=44 (44/min) analog=496 maxGap=0.63s wedges=0
+[  61.96s] progress: presses=226 (219/min) analog=952 maxGap=0.63s wedges=0
+[  91.97s] progress: presses=236 (154/min) analog=1428 maxGap=0.63s wedges=0
+
+== MASH SUMMARY [patched-e0t5-9600] ==
+run              : 120s on COM1, lamps on, wedge threshold 2.0s
+firmware         : 4.2
+presses/releases : 236 / 236  (115 presses/min)
+analog replies   : 1919 (~2181 poll slots; 88.0%), sentinels 0
+framing / NAK    : 75 / 0 (command resends NAK/timeout: 69)
+gap histogram    : <100ms:1911  100-250ms:5  250-500ms:0  0.5-1s:2  1-2s:0  2-5s:0  >5s:0
+longest gaps     : 0.66s@121.8s, 0.63s@0.6s, 0.14s@40.3s, 0.13s@42.0s, 0.13s@37.2s, 0.11s@76.9s, 0.11s@58.3s, 0.10s@53.4s, 0.10s@112.9s, 0.10s@35.4s
+wedge events     : 0
+counters before  : RestartCount=0  AbandonCount=0  FullBufferCount=0  [board/lamp faults reported!]
+counters after   : RestartCount=0  AbandonCount=0  FullBufferCount=0  [board/lamp faults reported!]
+counter delta    : RestartCount=+0  AbandonCount=+0  FullBufferCount=+0
+verdict          : PASS — no wedge; compare gap histogram + counter delta to baseline
+log file         : c:\VWE\riojoy\riomash-patched-e0t5-9600-20260719-154259.log