diff --git a/index.html b/index.html
index 403efb7..3987513 100644
--- a/index.html
+++ b/index.html
@@ -386,6 +386,11 @@
       <div id="lastConnected" class="gap-2">
         <span class="text-muted"><i class="fas fa-history"></i>&nbsp;&nbsp;<span class="ds-i18n">Last connected</span>:</span>
         <span id="lastConnectedInfo"></span>
+        <div id="lastConnectedWarning" style="display: none;">
+          <p class="text-danger" style="margin-top: 8px; margin-bottom: 0;">
+            <i class="fas fa-regular fa-triangle-exclamation"></i>&nbsp;&nbsp;<span class="ds-i18n">This controller has unsaved changes that will be lost when the controller is rebooted.</span>
+          </p>
+        </div>
       </div>
     </div>
   </div>
diff --git a/js/core.js b/js/core.js
index 2dc2aca..725c5c5 100644
--- a/js/core.js
+++ b/js/core.js
@@ -295,15 +295,14 @@ async function continue_connection({data, device}) {
     // Save controller info to local storage
     const lastConnectedInfo = {
       deviceName: deviceName,
-      timestamp: new Date().toISOString()
+      timestamp: new Date().toISOString(),
+      serialNumber: await controllerInstance.getSerialNumber(),
     };
 
     // Extract info from infoItems
     if (info.infoItems && Array.isArray(info.infoItems)) {
       for (const item of info.infoItems) {
-        if (item.key === l("Serial Number")) {
-          lastConnectedInfo.serialNumber = item.value;
-        } else if (item.key === l("Board Model")) {
+        if (item.key === l("Board Model")) {
           lastConnectedInfo.boardModel = item.value;
         } else if (item.key === l("Color")) {
           lastConnectedInfo.color = item.value;
@@ -428,6 +427,16 @@ function updateLastConnectedInfo() {
     }
 
     $infoDiv.text(text);
+
+    if (info.serialNumber) {
+      const storageKey = `changes_${info.serialNumber}`;
+      const savedChangesState = localStorage.getItem(storageKey);
+      const hasChanges = savedChangesState ? JSON.parse(savedChangesState) : false;
+
+      const $warning = $("#lastConnectedWarning");
+      $warning.toggle(hasChanges);
+    }
+
     $lastConnected.show();
   } catch (error) {
     console.error("Error parsing last connected info:", error);