diff --git a/ports/esp32/machine_i2s.c b/ports/esp32/machine_i2s.c
index 8832ad5e90..933e68684b 100644
--- a/ports/esp32/machine_i2s.c
+++ b/ports/esp32/machine_i2s.c
@@ -840,4 +840,6 @@ const mp_obj_type_t machine_i2s_type = {
     .locals_dict = (mp_obj_dict_t *)&machine_i2s_locals_dict,
 };
 
+MP_REGISTER_ROOT_POINTER(struct _machine_i2s_obj_t *machine_i2s_obj[I2S_NUM_MAX]);
+
 #endif // MICROPY_PY_MACHINE_I2S
diff --git a/ports/esp32/machine_pin.c b/ports/esp32/machine_pin.c
index 865face96f..b575626338 100644
--- a/ports/esp32/machine_pin.c
+++ b/ports/esp32/machine_pin.c
@@ -729,3 +729,5 @@ STATIC const mp_obj_type_t machine_pin_irq_type = {
     .call = machine_pin_irq_call,
     .locals_dict = (mp_obj_dict_t *)&machine_pin_irq_locals_dict,
 };
+
+MP_REGISTER_ROOT_POINTER(mp_obj_t machine_pin_irq_handler[40]);
diff --git a/ports/esp32/machine_timer.c b/ports/esp32/machine_timer.c
index 100b2aa1fb..8541bcbfdb 100644
--- a/ports/esp32/machine_timer.c
+++ b/ports/esp32/machine_timer.c
@@ -272,3 +272,5 @@ const mp_obj_type_t machine_timer_type = {
     .make_new = machine_timer_make_new,
     .locals_dict = (mp_obj_t)&machine_timer_locals_dict,
 };
+
+MP_REGISTER_ROOT_POINTER(struct _machine_timer_obj_t *machine_timer_obj_head);
diff --git a/ports/esp32/main.c b/ports/esp32/main.c
index 14b7e14c62..c543c5b645 100644
--- a/ports/esp32/main.c
+++ b/ports/esp32/main.c
@@ -265,3 +265,5 @@ void *esp_native_code_commit(void *buf, size_t len, void *reloc) {
     memcpy(p, buf, len);
     return p;
 }
+
+MP_REGISTER_ROOT_POINTER(mp_obj_t native_code_pointers);
diff --git a/ports/esp32/mpconfigport.h b/ports/esp32/mpconfigport.h
index 7cfce49d37..8dc3537e59 100644
--- a/ports/esp32/mpconfigport.h
+++ b/ports/esp32/mpconfigport.h
@@ -136,14 +136,6 @@
 
 #define MP_STATE_PORT MP_STATE_VM
 
-struct _machine_timer_obj_t;
-
-#define MICROPY_PORT_ROOT_POINTERS \
-    mp_obj_t machine_pin_irq_handler[40]; \
-    struct _machine_timer_obj_t *machine_timer_obj_head; \
-    struct _machine_i2s_obj_t *machine_i2s_obj[I2S_NUM_MAX]; \
-    mp_obj_t native_code_pointers; \
-
 // type definitions for the specific machine
 
 #define MICROPY_MAKE_POINTER_CALLABLE(p) ((void *)((mp_uint_t)(p)))