diff --git a/.circleci/config.yml b/.circleci/config.yml
index f37cb623..14dac9f5 100644
--- a/.circleci/config.yml
+++ b/.circleci/config.yml
@@ -4,8 +4,8 @@ jobs:
   test-remote:
     docker:
       - image: cimg/ruby:3.4
-      - image: mcr.microsoft.com/playwright:v1.64.0-noble
-        command: /bin/sh -c "cd /home/pwuser && npm install --no-save playwright-core@1.64.0 && ./node_modules/.bin/playwright-core install && ./node_modules/.bin/playwright-core run-server --port 8888 --host 0.0.0.0 --path /ws"
+      - image: mcr.microsoft.com/playwright:v1.64.1-noble
+        command: /bin/sh -c "cd /home/pwuser && npm install --no-save playwright-core@1.64.1 && ./node_modules/.bin/playwright-core install && ./node_modules/.bin/playwright-core run-server --port 8888 --host 0.0.0.0 --path /ws"
         environment:
           DEBUG: "pw:*"
         user: pwuser
diff --git a/development/CLI_VERSION b/development/CLI_VERSION
index 94057304..0936d60d 100644
--- a/development/CLI_VERSION
+++ b/development/CLI_VERSION
@@ -1 +1 @@
-1.64.0
+1.64.1
diff --git a/development/api.json b/development/api.json
index 6dd7362e..b80167bf 100644
--- a/development/api.json
+++ b/development/api.json
@@ -128529,7 +128529,10 @@
                         "overloadIndex": 0
                       }
                     ],
-                    "expression": "[Object]"
+                    "expression": "[Object]",
+                    "langAliases": {
+                      "default": "WebMCPToolAnnotations"
+                    }
                   },
                   "spec": [
                     {
diff --git a/development/upgrades/1.64.1.md b/development/upgrades/1.64.1.md
new file mode 100644
index 00000000..d9b2d167
--- /dev/null
+++ b/development/upgrades/1.64.1.md
@@ -0,0 +1,28 @@
+# Playwright 1.64.1 upstream review
+
+Source: [v1.64.0...v1.64.1](https://github.com/microsoft/playwright/compare/v1.64.0...v1.64.1).
+npm commit `cfe490d941f992655948eee8fd4fd94e1c4234bf`. Ruby gem: `1.64.0` → `1.64.1`.
+
+This is a patch release of five cherry-picks. None of them touch
+`packages/playwright-core/src/client/**` or `packages/protocol/**`, so no Ruby
+implementation changes are needed. The server fixes ship in the 1.64.1 driver.
+
+## Upstream PR review
+
+| PR / behavior | Ruby action | Client changes | Upstream tests |
+| --- | --- | --- | --- |
+| [#43217](https://github.com/microsoft/playwright/pull/43217) chore(dotnet): fix async suffix of optional-arg overloads, alias WebMCPToolAnnotations | Generated API check only. `api.json` gains a `langAliases` entry on `WebMCPTool.annotations`, which the generated Ruby wrappers and docs ignore. | None. | None. |
+| [#43249](https://github.com/microsoft/playwright/pull/43249) fix(chromium): disable AvoidCorsURLLoaderRestartOnRedirect (#43242) | Port the regression test. The fix is a Chromium launch switch carried by the driver. | None. | `page-route.spec.ts`: should not abort preflighted cross-origin redirect when a route is registered → `spec/integration/page/route_spec.rb` |
+| [#43250](https://github.com/microsoft/playwright/pull/43250) fix(electron): do not drop windows that have not navigated while connecting (#43247) | No action; server-side fix carried by the driver. The Ruby client has no Electron specs. | None. | `electron-app.spec.ts` (not ported) |
+| [#43354](https://github.com/microsoft/playwright/pull/43354) chore: mark v1.64.1 | Version bump only. | None. | None. |
+| [#43353](https://github.com/microsoft/playwright/pull/43353) docs: release notes for v1.64 Python | No action. | None. | None. |
+
+## Verification
+
+- Clean regeneration (`generate_api_json.sh` + `generate_api.rb`) produces identical
+  wrappers, docs and `unimplemented_examples.md`. The only generated diff is the
+  `langAliases` entry in `development/api.json`.
+- The new route spec fails on the 1.64.0 driver (`TypeError: Failed to fetch`) and
+  passes on 1.64.1.
+- Full Chromium suite on Ruby 4.0: **1,291 examples, 0 failures, 29 pending**.
+  Run with `CI=1 PLAYWRIGHT_CLI_EXECUTABLE_PATH=./node_modules/.bin/playwright-core bundle exec rspec`.
diff --git a/lib/playwright/version.rb b/lib/playwright/version.rb
index 78b80b66..a33f32ef 100644
--- a/lib/playwright/version.rb
+++ b/lib/playwright/version.rb
@@ -1,6 +1,6 @@
 # frozen_string_literal: true
 
 module Playwright
-  VERSION = '1.64.0'
-  COMPATIBLE_PLAYWRIGHT_VERSION = '1.64.0'
+  VERSION = '1.64.1'
+  COMPATIBLE_PLAYWRIGHT_VERSION = '1.64.1'
 end
diff --git a/spec/integration/page/route_spec.rb b/spec/integration/page/route_spec.rb
index aa49baa6..17f452d2 100644
--- a/spec/integration/page/route_spec.rb
+++ b/spec/integration/page/route_spec.rb
@@ -774,6 +774,34 @@
   #   expect(resp).toEqual(['electric', 'gas']);
   # });
 
+  # https://github.com/microsoft/playwright/issues/43242
+  it 'should not abort preflighted cross-origin redirect when a route is registered' do
+    allow_cors = ->(app) {
+      app.headers(
+        "Access-Control-Allow-Origin" => app.request.env["HTTP_ORIGIN"] || "*",
+        "Access-Control-Allow-Credentials" => "true",
+        "Access-Control-Allow-Headers" => "x-app-version",
+      )
+    }
+    file_url = "#{server_prefix}/file"
+    sinatra.options('/download') { allow_cors.call(self); status 204 }
+    sinatra.get('/download') { allow_cors.call(self); redirect file_url, 302 }
+    sinatra.options('/file') { allow_cors.call(self); status 204 }
+    sinatra.get('/file') { allow_cors.call(self); "file contents" }
+
+    with_page do |page|
+      page.goto(server_empty_page)
+      page.route('**/never-matches', ->(route, _) { route.continue })
+      result = page.evaluate(<<~JAVASCRIPT, arg: "#{server_cross_process_prefix}/download")
+      async (url) => {
+        const response = await fetch(url, { credentials: 'include', headers: { 'X-App-Version': '1.2.3' } });
+        return `${response.status} ${await response.text()}`;
+      }
+      JAVASCRIPT
+      expect(result).to eq("200 file contents")
+    end
+  end
+
   # it('should reject cors with disallowed credentials', async ({page, server}) => {
   #   await page.goto(server.EMPTY_PAGE);
   #   await page.route('**/cars', async route => {