diff --git a/pikit-web/assets/diaglog.js b/pikit-web/assets/diaglog.js
index 6091d8c..f041671 100644
--- a/pikit-web/assets/diaglog.js
+++ b/pikit-web/assets/diaglog.js
@@ -8,6 +8,7 @@ const uiBuffer = [];
 let uiEnabled = false;
 let uiLevel = "normal";
 let clickListenerAttached = false;
+let loading = false;
 
 function appendUi(level, msg, meta = null) {
   if (!uiEnabled) return;
@@ -50,6 +51,13 @@ export async function initDiagUI({ elements, toast }) {
   const { enableToggle, debugToggle, refreshBtn, clearBtn, copyBtn, downloadBtn, logBox, statusEl } =
     elements;
 
+  const setBusy = (on) => {
+    loading = on;
+    [refreshBtn, clearBtn, copyBtn, downloadBtn, enableToggle, debugToggle].forEach((el) => {
+      if (el) el.disabled = !!on;
+    });
+  };
+
   async function syncState() {
     const data = await getDiagLog();
     const state = data.state || {};
@@ -73,17 +81,30 @@ export async function initDiagUI({ elements, toast }) {
   }
 
   async function refresh() {
+    if (loading) return;
+    setBusy(true);
     try {
       const entries = await syncState();
       render(entries);
       toast?.("Diagnostics refreshed", "success");
     } catch (e) {
       toast?.(e.error || "Failed to load diagnostics", "error");
+      // retry once if failed
+      try {
+        const entries = await syncState();
+        render(entries);
+        toast?.("Diagnostics refreshed (after retry)", "success");
+      } catch {
+        // swallow
+      }
+    } finally {
+      setBusy(false);
     }
   }
 
   enableToggle?.addEventListener("change", async () => {
     try {
+      setBusy(true);
       uiEnabled = enableToggle.checked;
       await setDiagLevel({ enabled: uiEnabled, level: uiLevel });
       appendUi("info", `Diagnostics ${uiEnabled ? "enabled" : "disabled"}`);
@@ -92,11 +113,14 @@ export async function initDiagUI({ elements, toast }) {
     } catch (e) {
       toast?.(e.error || "Failed to save diagnostics setting", "error");
       enableToggle.checked = !enableToggle.checked;
+    } finally {
+      setBusy(false);
     }
   });
 
   debugToggle?.addEventListener("change", async () => {
     try {
+      setBusy(true);
       uiLevel = debugToggle.checked ? "debug" : "normal";
       await setDiagLevel({ enabled: uiEnabled, level: uiLevel });
       appendUi("info", `Diagnostics level set to ${uiLevel}`);
@@ -105,6 +129,8 @@ export async function initDiagUI({ elements, toast }) {
     } catch (e) {
       toast?.(e.error || "Failed to save level", "error");
       debugToggle.checked = uiLevel === "debug";
+    } finally {
+      setBusy(false);
     }
   });
 
@@ -112,12 +138,15 @@ export async function initDiagUI({ elements, toast }) {
 
   clearBtn?.addEventListener("click", async () => {
     try {
+      setBusy(true);
       await clearDiagLog();
       uiBuffer.length = 0;
       appendUi("info", "Cleared diagnostics");
       await refresh();
     } catch (e) {
       toast?.(e.error || "Failed to clear log", "error");
+    } finally {
+      setBusy(false);
     }
   });