diff --git a/ports/unix/modffi.c b/ports/unix/modffi.c
index ec252ef33e..b692af4df1 100644
--- a/ports/unix/modffi.c
+++ b/ports/unix/modffi.c
@@ -631,3 +631,5 @@ const mp_obj_module_t mp_module_ffi = {
     .base = { &mp_type_module },
     .globals = (mp_obj_dict_t *)&mp_module_ffi_globals,
 };
+
+MP_REGISTER_MODULE(MP_QSTR_ffi, mp_module_ffi, MICROPY_PY_FFI);
diff --git a/ports/unix/modjni.c b/ports/unix/modjni.c
index 4b95a0c67d..5d2beaa8dc 100644
--- a/ports/unix/modjni.c
+++ b/ports/unix/modjni.c
@@ -712,3 +712,5 @@ const mp_obj_module_t mp_module_jni = {
     .base = { &mp_type_module },
     .globals = (mp_obj_dict_t *)&mp_module_jni_globals,
 };
+
+MP_REGISTER_MODULE(MP_QSTR_jni, mp_module_jni, MICROPY_PY_JNI);
diff --git a/ports/unix/modtermios.c b/ports/unix/modtermios.c
index 7a578becb9..cce8c28ab3 100644
--- a/ports/unix/modtermios.c
+++ b/ports/unix/modtermios.c
@@ -148,3 +148,5 @@ const mp_obj_module_t mp_module_termios = {
     .base = { &mp_type_module },
     .globals = (mp_obj_dict_t *)&mp_module_termios_globals,
 };
+
+MP_REGISTER_MODULE(MP_QSTR_termios, mp_module_termios, MICROPY_PY_TERMIOS);
diff --git a/ports/unix/modtime.c b/ports/unix/modtime.c
index 71257c15ff..00b3f94367 100644
--- a/ports/unix/modtime.c
+++ b/ports/unix/modtime.c
@@ -232,4 +232,6 @@ const mp_obj_module_t mp_module_time = {
     .globals = (mp_obj_dict_t *)&mp_module_time_globals,
 };
 
+MP_REGISTER_MODULE(MP_QSTR_utime, mp_module_time, MICROPY_PY_UTIME);
+
 #endif // MICROPY_PY_UTIME
diff --git a/ports/unix/moduselect.c b/ports/unix/moduselect.c
index c88eb25edb..d3e0eff038 100644
--- a/ports/unix/moduselect.c
+++ b/ports/unix/moduselect.c
@@ -351,4 +351,6 @@ const mp_obj_module_t mp_module_uselect = {
     .globals = (mp_obj_dict_t *)&mp_module_select_globals,
 };
 
+MP_REGISTER_MODULE(MP_QSTR_uselect, mp_module_uselect, MICROPY_PY_USELECT_POSIX);
+
 #endif // MICROPY_PY_USELECT_POSIX
diff --git a/ports/unix/modusocket.c b/ports/unix/modusocket.c
index 5edff740f2..7526d9679d 100644
--- a/ports/unix/modusocket.c
+++ b/ports/unix/modusocket.c
@@ -701,3 +701,5 @@ const mp_obj_module_t mp_module_socket = {
     .base = { &mp_type_module },
     .globals = (mp_obj_dict_t *)&mp_module_socket_globals,
 };
+
+MP_REGISTER_MODULE(MP_QSTR_usocket, mp_module_socket, MICROPY_PY_SOCKET);
diff --git a/ports/unix/mpconfigport.h b/ports/unix/mpconfigport.h
index ef7c820e7e..524b165231 100644
--- a/ports/unix/mpconfigport.h
+++ b/ports/unix/mpconfigport.h
@@ -219,52 +219,6 @@ extern const struct _mp_print_t mp_stderr_print;
 #define mp_type_fileio mp_type_vfs_posix_fileio
 #define mp_type_textio mp_type_vfs_posix_textio
 
-extern const struct _mp_obj_module_t mp_module_uselect;
-extern const struct _mp_obj_module_t mp_module_time;
-extern const struct _mp_obj_module_t mp_module_termios;
-extern const struct _mp_obj_module_t mp_module_socket;
-extern const struct _mp_obj_module_t mp_module_ffi;
-extern const struct _mp_obj_module_t mp_module_jni;
-
-#if MICROPY_PY_FFI
-#define MICROPY_PY_FFI_DEF { MP_ROM_QSTR(MP_QSTR_ffi), MP_ROM_PTR(&mp_module_ffi) },
-#else
-#define MICROPY_PY_FFI_DEF
-#endif
-#if MICROPY_PY_JNI
-#define MICROPY_PY_JNI_DEF { MP_ROM_QSTR(MP_QSTR_jni), MP_ROM_PTR(&mp_module_jni) },
-#else
-#define MICROPY_PY_JNI_DEF
-#endif
-#if MICROPY_PY_UTIME
-#define MICROPY_PY_UTIME_DEF { MP_ROM_QSTR(MP_QSTR_utime), MP_ROM_PTR(&mp_module_time) },
-#else
-#define MICROPY_PY_UTIME_DEF
-#endif
-#if MICROPY_PY_TERMIOS
-#define MICROPY_PY_TERMIOS_DEF { MP_ROM_QSTR(MP_QSTR_termios), MP_ROM_PTR(&mp_module_termios) },
-#else
-#define MICROPY_PY_TERMIOS_DEF
-#endif
-#if MICROPY_PY_SOCKET
-#define MICROPY_PY_SOCKET_DEF { MP_ROM_QSTR(MP_QSTR_usocket), MP_ROM_PTR(&mp_module_socket) },
-#else
-#define MICROPY_PY_SOCKET_DEF
-#endif
-#if MICROPY_PY_USELECT_POSIX
-#define MICROPY_PY_USELECT_DEF { MP_ROM_QSTR(MP_QSTR_uselect), MP_ROM_PTR(&mp_module_uselect) },
-#else
-#define MICROPY_PY_USELECT_DEF
-#endif
-
-#define MICROPY_PORT_BUILTIN_MODULES \
-    MICROPY_PY_FFI_DEF \
-    MICROPY_PY_JNI_DEF \
-    MICROPY_PY_UTIME_DEF \
-    MICROPY_PY_SOCKET_DEF \
-    MICROPY_PY_USELECT_DEF \
-    MICROPY_PY_TERMIOS_DEF \
-
 // type definitions for the specific machine
 
 // For size_t and ssize_t
diff --git a/ports/windows/mpconfigport.h b/ports/windows/mpconfigport.h
index 1d78f00320..ecaa520e81 100644
--- a/ports/windows/mpconfigport.h
+++ b/ports/windows/mpconfigport.h
@@ -215,10 +215,6 @@ typedef long mp_off_t;
 #define MICROPY_PORT_BUILTINS \
     { MP_ROM_QSTR(MP_QSTR_open), MP_ROM_PTR(&mp_builtin_open_obj) },
 
-extern const struct _mp_obj_module_t mp_module_time;
-#define MICROPY_PORT_BUILTIN_MODULES \
-    { MP_ROM_QSTR(MP_QSTR_utime), MP_ROM_PTR(&mp_module_time) }, \
-
 #if MICROPY_USE_READLINE == 1
 #define MICROPY_PORT_ROOT_POINTERS \
     char *readline_hist[50];