diff --git a/shortfin/python/lib_ext.cc b/shortfin/python/lib_ext.cc
index c668e6a8b..af7aba767 100644
--- a/shortfin/python/lib_ext.cc
+++ b/shortfin/python/lib_ext.cc
@@ -672,7 +672,7 @@ void BindLocal(py::module_ &m) {
       // Methods not on System but on child objects, taking System as an arg.
       // Emitted here for convenience.
       .def("load_module", &local::ProgramModule::Load, py::arg("path"),
-           py::arg("mmap") = true);
+           py::arg("mmap") = false);
 
   // Support classes.
   py::class_<local::Node>(m, "Node")
@@ -731,7 +731,7 @@ void BindLocal(py::module_ &m) {
       .def_prop_ro("exports", &local::ProgramModule::exports)
       .def("__repr__", &local::ProgramModule::to_s)
       .def_static("load", &local::ProgramModule::Load, py::arg("system"),
-                  py::arg("path"), py::arg("mmap") = true)
+                  py::arg("path"), py::arg("mmap") = false)
       .def_static(
           "parameter_provider",
           [](local::System &system, py::args params) {
@@ -817,7 +817,7 @@ void BindLocal(py::module_ &m) {
           },
           py::arg("file_path"), py::arg("format") = std::string_view(),
           py::arg("readable") = true, py::arg("writable") = false,
-          py::arg("mmap") = true);
+          py::arg("mmap") = false);
 
   struct DevicesSet {
     DevicesSet(py::object fiber_obj, std::optional<size_t> index = {})
diff --git a/shortfin/src/shortfin/local/program.cc b/shortfin/src/shortfin/local/program.cc
index 0eefb572f..9744c1691 100644
--- a/shortfin/src/shortfin/local/program.cc
+++ b/shortfin/src/shortfin/local/program.cc
@@ -633,13 +633,29 @@ void StaticProgramParameters::Load(std::filesystem::path file_path,
     options.format = file_path.extension().string();
   }
 
-  // Open file.
-  iree_file_read_flags_t read_flags = IREE_FILE_READ_FLAG_DEFAULT;
   if (options.mmap) {
-    read_flags = IREE_FILE_READ_FLAG_MMAP;
-  } else {
-    read_flags = IREE_FILE_READ_FLAG_PRELOAD;
+    this->LoadMmap(file_path, options);
+    return;
   }
+
+  auto file_path_string = file_path.string();
+  const iree_string_view_t path =
+      iree_make_cstring_view(file_path_string.c_str());
+  iree_io_file_handle_t *file_handle = NULL;
+  SHORTFIN_THROW_IF_ERROR(iree_io_file_handle_open(
+      IREE_IO_FILE_MODE_READ, path, host_allocator_, &file_handle));
+
+  // Parse.
+  SHORTFIN_THROW_IF_ERROR(
+      iree_io_parse_file_index(to_iree_string_view(options.format), file_handle,
+                               index_.get(), host_allocator_));
+}
+
+void StaticProgramParameters::LoadMmap(std::filesystem::path file_path,
+                                       LoadOptions options) {
+  SHORTFIN_TRACE_SCOPE_NAMED("StaticProgramParameters::LoadMmap");
+
+  iree_file_read_flags_t read_flags = IREE_FILE_READ_FLAG_MMAP;
   iree_file_contents_t *file_contents = nullptr;
   SHORTFIN_THROW_IF_ERROR(iree_file_read_contents(
       file_path.string().c_str(), read_flags, host_allocator_, &file_contents));
diff --git a/shortfin/src/shortfin/local/program.h b/shortfin/src/shortfin/local/program.h
index 450b29736..f83b83cbd 100644
--- a/shortfin/src/shortfin/local/program.h
+++ b/shortfin/src/shortfin/local/program.h
@@ -265,7 +265,7 @@ class SHORTFIN_API ProgramModule {
 
   // Loads a dynamic bytecode module (VMFB) from a path on the file system.
   static ProgramModule Load(System &system, const std::filesystem::path &path,
-                            bool mmap = true);
+                            bool mmap = false);
 
   // Creates a ProgramModule that will provide the given list of parameters
   // to modules loaded after it. In IREE parlance, this produces an
@@ -386,7 +386,7 @@ class SHORTFIN_API StaticProgramParameters : public BaseProgramParameters {
     // Whether the backing file can be written.
     bool writable = false;
     // Whether to mmap the file.
-    bool mmap = true;
+    bool mmap = false;
   };
   // Load parameters from a supported file format, applying no name
   // transformation.
@@ -396,6 +396,8 @@ class SHORTFIN_API StaticProgramParameters : public BaseProgramParameters {
  private:
   iree_allocator_t host_allocator_;
   iree::io_parameter_index_ptr index_;
+
+  void LoadMmap(std::filesystem::path file_path, LoadOptions options);
 };
 
 namespace detail {