diff --git a/src/hub/reducers.test.ts b/src/hub/reducers.test.ts
index 87b081a24..b65c2d3d3 100644
--- a/src/hub/reducers.test.ts
+++ b/src/hub/reducers.test.ts
@@ -58,6 +58,7 @@ test('initial state', () => {
           "runtime": "hub.runtime.disconnected",
           "selectedSlot": 0,
           "useLegacyDownload": false,
+          "useLegacyMainModule": false,
           "useLegacyStartUserProgram": false,
           "useLegacyStdio": false,
         }
@@ -544,3 +545,23 @@ describe('useLegacyStartUserProgram', () => {
         ).toBeFalsy();
     });
 });
+
+describe('useLegacyMainModule', () => {
+    test('Pybricks Profile < v1.5.0', () => {
+        expect(
+            reducers(
+                { useLegacyMainModule: false } as State,
+                bleDIServiceDidReceiveSoftwareRevision('1.4.0'),
+            ).useLegacyMainModule,
+        ).toBeTruthy();
+    });
+
+    test('Pybricks Profile >= v1.5.0', () => {
+        expect(
+            reducers(
+                { useLegacyMainModule: true } as State,
+                bleDIServiceDidReceiveSoftwareRevision('1.5.0'),
+            ).useLegacyMainModule,
+        ).toBeFalsy();
+    });
+});
diff --git a/src/hub/reducers.ts b/src/hub/reducers.ts
index c4809250b..96df7f9ba 100644
--- a/src/hub/reducers.ts
+++ b/src/hub/reducers.ts
@@ -1,5 +1,5 @@
 // SPDX-License-Identifier: MIT
-// Copyright (c) 2020-2025 The Pybricks Authors
+// Copyright (c) 2020-2026 The Pybricks Authors
 
 import { Reducer, combineReducers } from 'redux';
 import * as semver from 'semver';
@@ -31,6 +31,7 @@ import {
     usbDidDisconnectPybricks,
     usbDidReceiveDeviceName,
     usbDidReceiveFirmwareRevision,
+    usbDidReceiveSoftwareRevision,
     usbDisconnectPybricks,
 } from '../usb/actions';
 import { pythonVersionToSemver } from '../utils/version';
@@ -361,7 +362,10 @@ const useLegacyDownload: Reducer<boolean> = (state = false, action) => {
  * When true, use NUS for stdio instead of Pybricks control characteristic.
  */
 const useLegacyStdio: Reducer<boolean> = (state = false, action) => {
-    if (bleDIServiceDidReceiveSoftwareRevision.matches(action)) {
+    if (
+        bleDIServiceDidReceiveSoftwareRevision.matches(action) ||
+        usbDidReceiveSoftwareRevision.matches(action)
+    ) {
         // Behavior changed starting with Pybricks Profile v1.3.0.
         return !semver.satisfies(action.version, '^1.3.0');
     }
@@ -373,7 +377,10 @@ const useLegacyStdio: Reducer<boolean> = (state = false, action) => {
  * When true, use Legacy StartUserProgram.
  */
 const useLegacyStartUserProgram: Reducer<boolean> = (state = false, action) => {
-    if (bleDIServiceDidReceiveSoftwareRevision.matches(action)) {
+    if (
+        bleDIServiceDidReceiveSoftwareRevision.matches(action) ||
+        usbDidReceiveSoftwareRevision.matches(action)
+    ) {
         // Behavior changed starting with Pybricks Profile v1.4.0.
         return !semver.satisfies(action.version, '^1.4.0');
     }
@@ -381,6 +388,21 @@ const useLegacyStartUserProgram: Reducer<boolean> = (state = false, action) => {
     return state;
 };
 
+/**
+ * When true, use the legacy `__main__` module name instead of the actual file name.
+ */
+const useLegacyMainModule: Reducer<boolean> = (state = false, action) => {
+    if (
+        bleDIServiceDidReceiveSoftwareRevision.matches(action) ||
+        usbDidReceiveSoftwareRevision.matches(action)
+    ) {
+        // Behavior changed starting with Pybricks Profile v1.5.0.
+        return !semver.satisfies(action.version, '^1.5.0');
+    }
+
+    return state;
+};
+
 /*
  * Returns number of available slots or 0 for slots not supported.
  */
@@ -418,6 +440,7 @@ export default combineReducers({
     useLegacyDownload,
     useLegacyStdio,
     useLegacyStartUserProgram,
+    useLegacyMainModule,
     numOfSlots,
     selectedSlot,
 });
diff --git a/src/mpy/sagas.ts b/src/mpy/sagas.ts
index b7b295980..b8c284a1e 100644
--- a/src/mpy/sagas.ts
+++ b/src/mpy/sagas.ts
@@ -1,5 +1,5 @@
 // SPDX-License-Identifier: MIT
-// Copyright (c) 2020-2023 The Pybricks Authors
+// Copyright (c) 2020-2026 The Pybricks Authors
 
 import { compile as mpyCrossCompileV5 } from '@pybricks/mpy-cross-v5';
 import { compile as mpyCrossCompileV6 } from '@pybricks/mpy-cross-v6';
@@ -104,8 +104,8 @@ function* handleCompile(action: ReturnType<typeof compile>): Generator {
 /**
  * Compiles code into the Pybricks multi-mpy6 file format.
  *
- * This includes a __main__ module which is the file currently open in the
- * editor and any imported modules that can be found in the user file system.
+ * This includes the file currently open in the editor and any imported modules
+ * that can be found in the user file system.
  */
 function* handleCompileMulti6(): Generator {
     // REVISIT: should we be getting the active file here or have it as an
@@ -128,14 +128,22 @@ function* handleCompileMulti6(): Generator {
         return;
     }
 
-    const mainPy = yield* editorGetValue();
+    const useLegacyMainModule = yield* select(
+        (s: RootState) => s.hub.useLegacyMainModule,
+    );
+
+    const mainPyContents = yield* editorGetValue();
+    const mainPyPath = metadata.path ?? '__main__.py';
+    const mainPyName = useLegacyMainModule
+        ? '__main__'
+        : mainPyPath.replace(/\.[^.]+$/, '');
 
     const pyFiles = new Map<string, FileContents>([
-        ['__main__', { path: metadata.path ?? '__main__.py', contents: mainPy }],
+        [mainPyName, { path: mainPyPath, contents: mainPyContents }],
     ]);
 
-    const checkedModules = new Set<string>(['__main__']);
-    const uncheckedScripts = new Array<string>(mainPy);
+    const checkedModules = new Set<string>([mainPyName]);
+    const uncheckedScripts = new Array<string>(mainPyContents);
 
     for (;;) {
         // parse all unchecked scripts to find imported modules that haven't