diff --git a/src/plugins/fresco/ImagesSidebar.js b/src/plugins/fresco/ImagesSidebar.js
index 0c20dc72c..49e4a950d 100644
--- a/src/plugins/fresco/ImagesSidebar.js
+++ b/src/plugins/fresco/ImagesSidebar.js
@@ -116,9 +116,9 @@ class EventDetails extends Component<{
           <DataDescriptionKey>Requested on cold start</DataDescriptionKey>
           <span key="sep">: </span>
           <DataDescription
-            type="number"
+            type="boolean"
             value={event.coldStart}
-            setValue={function(path: Array<string>, val: any) {}}
+            setValue={null}
           />
         </p>
         {this.renderViewportData()}
diff --git a/src/plugins/fresco/api.js b/src/plugins/fresco/api.js
index 3500e66fd..73fc6f934 100644
--- a/src/plugins/fresco/api.js
+++ b/src/plugins/fresco/api.js
@@ -58,7 +58,7 @@ export type ImageEvent = {
   startTime: Timestamp,
   endTime: Timestamp,
   source: string,
-  coldStart: number,
+  coldStart: boolean,
   viewport?: ViewportData, // not set for prefetches
 };