diff --git a/README.md b/README.md
index 1dd5513..6d24832 100644
--- a/README.md
+++ b/README.md
@@ -208,6 +208,7 @@ custom:
 ```
 
 ## Change Log
+* v1.2.1: Fix custom-resource bucket compatibility with serverless >3.39.0, continue improving support for `AWS_ENDPOINT_URL`
 * v1.2.0: Add docker-compose config and fix autostart when plugin is not active 
 * v1.1.3: Fix replacing host from environment variable `AWS_ENDPOINT_URL`
 * v1.1.2: Unify construction of target endpoint URL, add support for configuring `AWS_ENDPOINT_URL`
diff --git a/package-lock.json b/package-lock.json
index 29092b8..e0c71f9 100644
--- a/package-lock.json
+++ b/package-lock.json
@@ -1,12 +1,12 @@
 {
   "name": "serverless-localstack",
-  "version": "1.2.0",
+  "version": "1.2.1",
   "lockfileVersion": 2,
   "requires": true,
   "packages": {
     "": {
       "name": "serverless-localstack",
-      "version": "1.2.0",
+      "version": "1.2.1",
       "license": "MIT",
       "dependencies": {
         "adm-zip": "^0.5.10",
diff --git a/package.json b/package.json
index fc4d5a8..a6ab713 100644
--- a/package.json
+++ b/package.json
@@ -1,6 +1,6 @@
 {
   "name": "serverless-localstack",
-  "version": "1.2.0",
+  "version": "1.2.1",
   "description": "Connect Serverless to LocalStack!",
   "main": "src/index.js",
   "scripts": {
diff --git a/src/index.js b/src/index.js
index 07efa9f..fec99f7 100644
--- a/src/index.js
+++ b/src/index.js
@@ -985,6 +985,50 @@ class LocalstackPlugin {
         return;
       }
     }
+  
+    function patchPreV3() {
+      const utilFile = customResources.getEntry('utils.js');
+      if (utilFile == null) return;
+      const data = utilFile.getData().toString();
+      const legacyPatch = 'AWS.config.s3ForcePathStyle = true;';
+      if (data.includes(legacyPatch)) {
+        createPatchMarker();
+        return true;
+      }
+      const patchIndex = data.indexOf('AWS.config.logger = console;');
+      if (patchIndex === -1) {
+        return false;
+      }
+      const newData =
+        data.slice(0, patchIndex) + legacyPatch + '\n' + data.slice(patchIndex);
+      utilFile.setData(newData);
+      return true;
+    }
+
+    function patchV3() {
+      this.debug(
+        'serverless-localstack: Patching V3',
+      );
+      const customResourcesBucketFile = customResources.getEntry('s3/lib/bucket.js');
+      if (customResourcesBucketFile == null) {
+        // TODO debugging, remove
+        this.log(
+          'serverless-localstack: Could not find file s3/lib/bucket.js to patch.',
+        );
+        return;
+      }
+      const data = customResourcesBucketFile.getData().toString();
+      const oldClientCreation = 'S3Client({ maxAttempts: MAX_AWS_REQUEST_TRY });';
+      const newClientCreation = 'S3Client({ maxAttempts: MAX_AWS_REQUEST_TRY, forcePathStyle: true });';
+      if (data.includes(newClientCreation)) {
+        // patch already done
+        createPatchMarker();
+        return;
+      }
+      const newData = data.replace(oldClientCreation, newClientCreation);
+        
+      customResourcesBucketFile.setData(newData);
+    }
 
     if (fileExists(patchMarker)) {
       this.debug(
@@ -1000,18 +1044,10 @@ class LocalstackPlugin {
     }
 
     const customResources = new AdmZip(zipFilePath);
-    const utilFile = customResources.getEntry('utils.js');
-    if (utilFile == null) return;
-    const data = utilFile.getData().toString();
-    const patch = 'AWS.config.s3ForcePathStyle = true;';
-    if (data.includes(patch)) {
-      createPatchMarker();
-      return;
+
+    if (!patchPreV3.call(this)) {
+      patchV3.call(this);
     }
-    const indexPatch = data.indexOf('AWS.config.logger = console;');
-    const newData =
-      data.slice(0, indexPatch) + patch + '\n' + data.slice(indexPatch);
-    utilFile.setData(newData);
     customResources.writeZip();
     createPatchMarker();
     this.debug(