diff --git a/openhands/runtime/base.py b/openhands/runtime/base.py
index e517399df3..b494e380e3 100644
--- a/openhands/runtime/base.py
+++ b/openhands/runtime/base.py
@@ -135,10 +135,6 @@ class Runtime(FileEditRuntimeMixin):
         atexit.register(self.close)
 
         self.initial_env_vars = _default_env_vars(config.sandbox)
-
-        # also update with runtime_startup_env_vars
-        self.initial_env_vars.update(self.config.sandbox.runtime_startup_env_vars)
-
         if env_vars is not None:
             self.initial_env_vars.update(env_vars)
 
diff --git a/openhands/runtime/impl/docker/docker_runtime.py b/openhands/runtime/impl/docker/docker_runtime.py
index c42890e0c7..883877cafe 100644
--- a/openhands/runtime/impl/docker/docker_runtime.py
+++ b/openhands/runtime/impl/docker/docker_runtime.py
@@ -23,7 +23,7 @@ from openhands.runtime.impl.action_execution.action_execution_client import (
 from openhands.runtime.impl.docker.containers import stop_all_containers
 from openhands.runtime.plugins import PluginRequirement
 from openhands.runtime.utils import find_available_tcp_port
-from openhands.runtime.utils.command import DEFAULT_MAIN_MODULE, get_action_execution_server_startup_command
+from openhands.runtime.utils.command import get_action_execution_server_startup_command
 from openhands.runtime.utils.log_streamer import LogStreamer
 from openhands.runtime.utils.runtime_build import build_runtime_image
 from openhands.utils.async_utils import call_sync_from_async
@@ -80,7 +80,6 @@ class DockerRuntime(ActionExecutionClient):
         status_callback: Callable | None = None,
         attach_to_existing: bool = False,
         headless_mode: bool = True,
-        main_module: str = DEFAULT_MAIN_MODULE,
     ):
         if not DockerRuntime._shutdown_listener_id:
             DockerRuntime._shutdown_listener_id = add_shutdown_listener(
@@ -110,7 +109,6 @@ class DockerRuntime(ActionExecutionClient):
         self.runtime_container_image = self.config.sandbox.runtime_container_image
         self.container_name = CONTAINER_NAME_PREFIX + sid
         self.container: Container | None = None
-        self.main_module = main_module
 
         self.runtime_builder = DockerRuntimeBuilder(self.docker_client)
 
@@ -311,15 +309,16 @@ class DockerRuntime(ActionExecutionClient):
             )
 
         # Combine environment variables
-        environment = dict(**self.initial_env_vars)
-        environment.update({
+        environment = {
             'port': str(self._container_port),
             'PYTHONUNBUFFERED': '1',
             'VSCODE_PORT': str(self._vscode_port),
             'PIP_BREAK_SYSTEM_PACKAGES': '1',
-        })
+        }
         if self.config.debug or DEBUG:
             environment['DEBUG'] = 'true'
+        # also update with runtime_startup_env_vars
+        environment.update(self.config.sandbox.runtime_startup_env_vars)
 
         self.log('debug', f'Workspace Base: {self.config.workspace_base}')
 
@@ -337,7 +336,11 @@ class DockerRuntime(ActionExecutionClient):
             f'Sandbox workspace: {self.config.workspace_mount_path_in_sandbox}',
         )
 
-        command = self.get_action_execution_server_startup_command()
+        command = get_action_execution_server_startup_command(
+            server_port=self._container_port,
+            plugins=self.plugins,
+            app_config=self.config,
+        )
 
         try:
             self.container = self.docker_client.containers.run(
@@ -531,11 +534,3 @@ class DockerRuntime(ActionExecutionClient):
             pass
         finally:
             docker_client.close()
-
-    def get_action_execution_server_startup_command(self):
-        return get_action_execution_server_startup_command(
-            server_port=self._container_port,
-            plugins=self.plugins,
-            app_config=self.config,
-            main_module=self.main_module,
-        )
diff --git a/openhands/runtime/impl/remote/remote_runtime.py b/openhands/runtime/impl/remote/remote_runtime.py
index ba0469381e..ae47137807 100644
--- a/openhands/runtime/impl/remote/remote_runtime.py
+++ b/openhands/runtime/impl/remote/remote_runtime.py
@@ -24,7 +24,7 @@ from openhands.runtime.impl.action_execution.action_execution_client import (
     ActionExecutionClient,
 )
 from openhands.runtime.plugins import PluginRequirement
-from openhands.runtime.utils.command import DEFAULT_MAIN_MODULE, get_action_execution_server_startup_command
+from openhands.runtime.utils.command import get_action_execution_server_startup_command
 from openhands.runtime.utils.request import send_request
 from openhands.runtime.utils.runtime_build import build_runtime_image
 from openhands.utils.async_utils import call_sync_from_async
@@ -54,7 +54,6 @@ class RemoteRuntime(ActionExecutionClient):
         headless_mode: bool = True,
         user_id: str | None = None,
         git_provider_tokens: PROVIDER_TOKEN_TYPE | None = None,
-        main_module: str = DEFAULT_MAIN_MODULE,
     ) -> None:
         super().__init__(
             config,
@@ -86,7 +85,6 @@ class RemoteRuntime(ActionExecutionClient):
             )
 
         assert self.config.sandbox.remote_runtime_class in (None, 'sysbox', 'gvisor')
-        self.main_module = main_module
 
         self.runtime_builder = RemoteRuntimeBuilder(
             self.config.sandbox.remote_runtime_api_url,
@@ -233,7 +231,11 @@ class RemoteRuntime(ActionExecutionClient):
 
     def _start_runtime(self) -> None:
         # Prepare the request body for the /start endpoint
-        command = self.get_action_execution_server_startup_command()
+        command = get_action_execution_server_startup_command(
+            server_port=self.port,
+            plugins=self.plugins,
+            app_config=self.config,
+        )
         environment: dict[str, str] = {}
         if self.config.debug or os.environ.get('DEBUG', 'false').lower() == 'true':
             environment['DEBUG'] = 'true'
@@ -490,11 +492,3 @@ class RemoteRuntime(ActionExecutionClient):
 
     def _stop_if_closed(self, retry_state: RetryCallState) -> bool:
         return self._runtime_closed
-
-    def get_action_execution_server_startup_command(self):
-        return get_action_execution_server_startup_command(
-            server_port=self.port,
-            plugins=self.plugins,
-            app_config=self.config,
-            main_module=self.main_module,
-        )
diff --git a/openhands/runtime/utils/command.py b/openhands/runtime/utils/command.py
index 66787b2e28..b2485d09fb 100644
--- a/openhands/runtime/utils/command.py
+++ b/openhands/runtime/utils/command.py
@@ -9,7 +9,6 @@ DEFAULT_PYTHON_PREFIX = [
     'poetry',
     'run',
 ]
-DEFAULT_MAIN_MODULE = 'openhands.runtime.action_execution_server'
 
 
 def get_action_execution_server_startup_command(
@@ -19,7 +18,6 @@ def get_action_execution_server_startup_command(
     python_prefix: list[str] = DEFAULT_PYTHON_PREFIX,
     override_user_id: int | None = None,
     override_username: str | None = None,
-    main_module: str = DEFAULT_MAIN_MODULE,
 ) -> list[str]:
     sandbox_config = app_config.sandbox
 
@@ -47,7 +45,7 @@ def get_action_execution_server_startup_command(
         'python',
         '-u',
         '-m',
-        main_module,
+        'openhands.runtime.action_execution_server',
         str(server_port),
         '--working-dir',
         app_config.workspace_mount_path_in_sandbox,