diff --git a/scripts/check-component-externals.mjs b/scripts/check-component-externals.mjs
index d27416736..28aef6c1f 100644
--- a/scripts/check-component-externals.mjs
+++ b/scripts/check-component-externals.mjs
@@ -44,8 +44,9 @@ const TARGETS = [
   {
     config: "vite-component.config.ts",
     what: "the component build",
-    sources: ["src", "component"],
-    excluded: ["component/dev"],
+    // `sdk` too: the build resolves `@element-hq/matrixrtc-sdk` to its source
+    sources: ["src", "component", "sdk"],
+    excluded: ["component/dev", "sdk/dev"],
     mustBeExternal: [
       "react",
       "react-dom",
diff --git a/vite-component.config.ts b/vite-component.config.ts
index fa6ce4168..63183c781 100644
--- a/vite-component.config.ts
+++ b/vite-component.config.ts
@@ -89,6 +89,7 @@ export default defineConfig(({ mode }) => {
           "react-dom",
           "react-dom/client",
           "matrix-js-sdk",
+          "matrix-js-sdk/lib/@types/event",
           "matrix-js-sdk/lib/browser-index",
           "matrix-js-sdk/lib/client",
           "matrix-js-sdk/lib/crypto-api",
@@ -99,8 +100,10 @@ export default defineConfig(({ mode }) => {
           "matrix-js-sdk/lib/matrixrtc/EncryptionManager",
           "matrix-js-sdk/lib/matrixrtc/IKeyTransport",
           "matrix-js-sdk/lib/matrixrtc/IMembershipManager",
+          "matrix-js-sdk/lib/models/event",
           "matrix-js-sdk/lib/models/relations-container",
           "matrix-js-sdk/lib/models/room",
+          "matrix-js-sdk/lib/models/room-state",
           "matrix-js-sdk/lib/models/typed-event-emitter",
           "matrix-js-sdk/lib/randomstring",
           "matrix-js-sdk/lib/sync",