diff --git a/docs/_javascript/preset_test.js b/docs/_javascript/preset_test.js
index 7fdfefbe..e059e1b8 100644
--- a/docs/_javascript/preset_test.js
+++ b/docs/_javascript/preset_test.js
@@ -13,6 +13,8 @@
     7.8, 10.4, 15.6, 20.8, 31.25, 41.7, 62.5, 125, 250, 500,
   ]);
   const SCHEDULE_HORIZON_MS = 0x7fffffff;
+  const EARLY_JOIN_MS = 60 * 60 * 1000;
+  const CLOCK_RESET_COMMAND = "clkreboot";
 
   class PresetTestError extends Error {}
 
@@ -121,6 +123,10 @@
     return Math.max(0, Math.ceil((config.endMs - nowMs) / 60000));
   }
 
+  function immediateAvailable(config, nowMs) {
+    return nowMs >= config.startMs - EARLY_JOIN_MS && nowMs < config.endMs;
+  }
+
   function scheduleAvailability(config, nowMs) {
     if (nowMs >= config.startMs) {
       return { available: false, reason: "The start time has passed; use the immediate option." };
@@ -302,6 +308,7 @@
     setCommand(root, "stock-cancel-during", staticCommands.stockCancelDuring);
     setCommand(root, "companion-cancel-before", staticCommands.companionCancelBefore);
     setCommand(root, "companion-cancel-during", staticCommands.companionCancelDuring);
+    setCommand(root, "reset-clock", CLOCK_RESET_COMMAND);
     setCommand(
       root,
       "share-url",
@@ -321,16 +328,28 @@
     function render() {
       const nowMs = Date.now();
       const phase = phaseAt(config, nowMs);
+      const immediateOpen = immediateAvailable(config, nowMs);
       const status = root.querySelector('[data-role="status"]');
       const schedule = scheduleAvailability(config, nowMs);
       const commands = commandsFor(config, nowMs);
 
       status.dataset.state = phase;
       if (phase === "before") {
-        status.textContent = "Scheduled";
-        setText(root, '[data-role="countdown-label"]', "Starts in");
-        setText(root, '[data-role="countdown"]', formatCountdown(config.startMs - nowMs));
-        setText(root, '[data-role="countdown-detail"]', "Do not use immediate TempRadio yet.");
+        if (immediateOpen) {
+          status.textContent = "Setup window open";
+          setText(root, '[data-role="countdown-label"]', "Test starts in");
+          setText(root, '[data-role="countdown"]', formatCountdown(config.startMs - nowMs));
+          setText(root, '[data-role="countdown-detail"]', "Immediate TempRadio commands are enabled.");
+        } else {
+          status.textContent = "Scheduled";
+          setText(root, '[data-role="countdown-label"]', "Commands open in");
+          setText(
+            root,
+            '[data-role="countdown"]',
+            formatCountdown(config.startMs - EARLY_JOIN_MS - nowMs)
+          );
+          setText(root, '[data-role="countdown-detail"]', "The setup window opens one hour before the test.");
+        }
       } else if (phase === "active") {
         status.textContent = "Test live";
         setText(root, '[data-role="countdown-label"]', "Ends in");
@@ -343,25 +362,27 @@
         setText(root, '[data-role="countdown-detail"]', "Temporary radios should be back on saved settings.");
       }
 
-      if (phase === "active") {
+      if (immediateOpen) {
         setCommand(root, "stock-now", commands.stockNow);
         setCommand(root, "companion-now", commands.companionNow);
       } else {
         const unavailable = phase === "before"
-          ? "Available when the test starts — use Option 2 to schedule now."
+          ? "Available one hour before the test — use Option 2 to schedule now."
           : "Test window ended — do not start TempRadio.";
         setCommand(root, "stock-now", unavailable);
         setCommand(root, "companion-now", unavailable);
       }
-      setCommandEnabled(root, "stock-now", phase === "active");
-      setCommandEnabled(root, "companion-now", phase === "active");
-      setMaterialCommandCopyEnabled(root, "stock-now", phase === "active");
-      setMaterialCommandCopyEnabled(root, "companion-now", phase === "active");
+      setCommandEnabled(root, "stock-now", immediateOpen);
+      setCommandEnabled(root, "companion-now", immediateOpen);
+      setMaterialCommandCopyEnabled(root, "stock-now", immediateOpen);
+      setMaterialCommandCopyEnabled(root, "companion-now", immediateOpen);
       setText(
         root,
         '[data-role="stock-now-note"]',
-        phase === "before"
-          ? "Available when the test starts; schedule it now with Option 2."
+        phase === "before" && !immediateOpen
+          ? "Available one hour before the test; schedule it now with Option 2."
+          : phase === "before"
+            ? "The setup window is open; the timeout includes the hour before the official start."
           : phase === "active"
             ? "The final argument is the live minutes remaining until the common end."
             : "The test window has ended."
@@ -380,7 +401,7 @@
     render();
     if (typeof global.MutationObserver === "function") {
       const materialCopyObserver = new global.MutationObserver(function () {
-        const enabled = phaseAt(config, Date.now()) === "active";
+        const enabled = immediateAvailable(config, Date.now());
         setMaterialCommandCopyEnabled(root, "stock-now", enabled);
         setMaterialCommandCopyEnabled(root, "companion-now", enabled);
       });
@@ -393,10 +414,13 @@
     DEFAULTS: DEFAULTS,
     VALID_BANDWIDTHS: VALID_BANDWIDTHS,
     SCHEDULE_HORIZON_MS: SCHEDULE_HORIZON_MS,
+    EARLY_JOIN_MS: EARLY_JOIN_MS,
+    CLOCK_RESET_COMMAND: CLOCK_RESET_COMMAND,
     PresetTestError: PresetTestError,
     configFromSearch: configFromSearch,
     phaseAt: phaseAt,
     remainingMinutes: remainingMinutes,
+    immediateAvailable: immediateAvailable,
     scheduleAvailability: scheduleAvailability,
     commandsFor: commandsFor,
     formatCountdown: formatCountdown,
diff --git a/docs/_stylesheets/preset_test.css b/docs/_stylesheets/preset_test.css
index 0913991c..30df5b77 100644
--- a/docs/_stylesheets/preset_test.css
+++ b/docs/_stylesheets/preset_test.css
@@ -163,6 +163,10 @@
   background: var(--md-default-bg-color);
 }
 
+.preset-test-card--wide {
+  grid-column: 1 / -1;
+}
+
 .preset-test-card h3 {
   margin-top: 0;
 }
diff --git a/docs/preset_test.md b/docs/preset_test.md
index 21347414..b1cadb1b 100644
--- a/docs/preset_test.md
+++ b/docs/preset_test.md
@@ -99,6 +99,20 @@ clock</code></pre>
 clock</code></pre>
           <button type="button" data-copy-command="set-clock">Copy current clock command</button>
         </article>
+
+        <article class="preset-test-card preset-test-card--wide">
+          <h3>If the clock is ahead and cannot move backward</h3>
+          <p>
+            If setting the correct time returns <code>ERR: clock cannot go backwards</code>,
+            run the command below. It resets the clock to an older fallback date and
+            reboots the node immediately, so it sends no reply. After the node reconnects,
+            copy and run the fresh local clock command above, verify with <code>clock</code>,
+            and then add the <code>tempradioat</code> schedule again. The reboot clears any
+            pending scheduled entries.
+          </p>
+          <pre><code data-command="reset-clock">clkreboot</code></pre>
+          <button type="button" data-copy-command="reset-clock">Copy clock reset command</button>
+        </article>
       </div>
 
       <p class="preset-test-note">
@@ -109,11 +123,12 @@ clock</code></pre>
     </section>
 
     <section aria-labelledby="join-now-title">
-      <h2 id="join-now-title">Option 1: switch when the test begins</h2>
+      <h2 id="join-now-title">Option 1: switch during the setup window</h2>
       <p>
-        Open this page after the start time. Its timeout shrinks so every node
-        returns at the same end time. These copy buttons remain disabled before
-        the window to prevent an early switch.
+        The immediate commands become available one hour before the official
+        start. Their timeout shrinks so every node still returns at the same end
+        time. Before that setup window, the command text and copy controls stay
+        unavailable.
       </p>
 
       <div class="preset-test-grid">
diff --git a/test/test_preset_test.js b/test/test_preset_test.js
index 7cf3dc7a..11e81c85 100644
--- a/test/test_preset_test.js
+++ b/test/test_preset_test.js
@@ -21,12 +21,22 @@ assert.strictEqual(defaults.endEpoch, config.endEpoch);
 assert.strictEqual(defaults.freq, config.freq);
 
 const before = Date.parse("2026-09-21T16:59:00-07:00");
+const beforeSetup = Date.parse("2026-09-21T15:59:59-07:00");
+const setupOpens = Date.parse("2026-09-21T16:00:00-07:00");
 const active = Date.parse("2026-09-21T17:00:30-07:00");
 const ended = Date.parse("2026-09-23T17:00:00-07:00");
 assert.strictEqual(tool.phaseAt(config, before), "before");
 assert.strictEqual(tool.phaseAt(config, active), "active");
 assert.strictEqual(tool.phaseAt(config, ended), "ended");
+assert.strictEqual(tool.EARLY_JOIN_MS, 60 * 60 * 1000);
+assert.strictEqual(tool.CLOCK_RESET_COMMAND, "clkreboot");
+assert.strictEqual(tool.immediateAvailable(config, beforeSetup), false);
+assert.strictEqual(tool.immediateAvailable(config, setupOpens), true);
+assert.strictEqual(tool.immediateAvailable(config, before), true);
+assert.strictEqual(tool.immediateAvailable(config, active), true);
+assert.strictEqual(tool.immediateAvailable(config, ended), false);
 assert.strictEqual(tool.remainingMinutes(config, active), 2880);
+assert.strictEqual(tool.remainingMinutes(config, setupOpens), 2940);
 
 const commands = tool.commandsFor(config, active);
 assert.strictEqual(commands.stockNow, "tempradio 910.1,500,8,7,2880");