diff --git a/src/js/messaging.js b/src/js/messaging.js
index 1566c709d..4021fe5d4 100644
--- a/src/js/messaging.js
+++ b/src/js/messaging.js
@@ -926,6 +926,16 @@ const backupUserData = async function() {
 const restoreUserData = async function(request) {
     const userData = request.userData;
 
+    // https://github.com/LiCybora/NanoDefenderFirefox/issues/196
+    //   Backup data could be from Chromium platform or from an older
+    //   Firefox version.
+    if (
+        vAPI.webextFlavor.soup.has('firefox') &&
+        vAPI.app.intFromVersion(userData.version) <= 1031003011
+    ) {
+        userData.hostnameSwitchesString += '\nno-csp-reports: * true';
+    }
+
     // https://github.com/chrisaljoudi/uBlock/issues/1102
     //   Ensure all currently cached assets are flushed from storage AND memory.
     µb.assets.rmrf();
diff --git a/src/js/start.js b/src/js/start.js
index 7ac10c0f0..79a1a441a 100644
--- a/src/js/start.js
+++ b/src/js/start.js
@@ -114,8 +114,11 @@ const onVersionReady = function(lastVersion) {
     if ( lastVersionInt === 0 ) { return; }
 
     // https://github.com/LiCybora/NanoDefenderFirefox/issues/196
-    //   Toggle on the blocking of CSP reports by default.
-    if ( lastVersionInt <= 1031003011 ) {
+    //   Toggle on the blocking of CSP reports by default for Firefox.
+    if (
+        vAPI.webextFlavor.soup.has('firefox') &&
+        lastVersionInt <= 1031003011
+    ) {
         µb.sessionSwitches.toggle('no-csp-reports', '*', 1);
         µb.permanentSwitches.toggle('no-csp-reports', '*', 1);
         µb.saveHostnameSwitches();