diff --git a/scripts/build.mjs b/scripts/build.mjs
index e3006349..a8f86fe9 100644
--- a/scripts/build.mjs
+++ b/scripts/build.mjs
@@ -221,7 +221,11 @@ async function buildJsLegacy(inputFile, outputName, extraFile, polyfillFile) {
                 {
                     useBuiltIns: "entry",
                     corejs: "3",
-                    targets: "IE 11"
+                    targets: "IE 11",
+                    // we provide our own promise polyfill (es6-promise)
+                    // with support for synchronous flushing of
+                    // the queue for idb where needed 
+                    exclude: ["es.promise", "es.promise.all-settled", "es.promise.finally"]
                 }
             ]
         ]
diff --git a/src/legacy-polyfill.js b/src/legacy-polyfill.js
index 75276384..c373d125 100644
--- a/src/legacy-polyfill.js
+++ b/src/legacy-polyfill.js
@@ -15,8 +15,6 @@ limitations under the License.
 */
 
 // polyfills needed for IE11
-
-// TODO: don't include a polyfill for promises as we already provide one
 import "core-js/stable";
 import "regenerator-runtime/runtime";
 import "mdn-polyfills/Element.prototype.closest";
diff --git a/src/worker-polyfill.js b/src/worker-polyfill.js
index ad13df3a..b9e80e36 100644
--- a/src/worker-polyfill.js
+++ b/src/worker-polyfill.js
@@ -18,7 +18,6 @@ limitations under the License.
 // polyfills needed for IE11
 // just enough to run olm, have promises and async/await
 import "regenerator-runtime/runtime";
-import "core-js/modules/es.promise";
 import "core-js/modules/es.math.imul";
 import "core-js/modules/es.math.clz32";