diff --git a/py/gc.c b/py/gc.c
index acb7edf873..cccc096e57 100644
--- a/py/gc.c
+++ b/py/gc.c
@@ -1099,6 +1099,38 @@ void *gc_realloc(void *ptr_in, size_t n_bytes, bool allow_move) {
 }
 #endif // Alternative gc_realloc impl
 
+bool gc_never_free(void *ptr) {
+    // Check to make sure the pointer is on the heap in the first place.
+    if (gc_nbytes(ptr) == 0) {
+        return false;
+    }
+    // Pointers are stored in a linked list where each block is BYTES_PER_BLOCK long and the first
+    // pointer is the next block of pointers.
+    void **current_reference_block = MP_STATE_MEM(permanent_pointers);
+    void **last_reference_block = NULL;
+    while (current_reference_block != NULL) {
+        for (size_t i = 1; i < BYTES_PER_BLOCK / sizeof(void *); i++) {
+            if (current_reference_block[i] == NULL) {
+                current_reference_block[i] = ptr;
+                return true;
+            }
+        }
+        last_reference_block = current_reference_block; // keep a record of last "proper" reference block
+        current_reference_block = current_reference_block[0];
+    }
+    void **next_block = gc_alloc(BYTES_PER_BLOCK, false);
+    if (next_block == NULL) {
+        return false;
+    }
+    if (MP_STATE_MEM(permanent_pointers) == NULL) {
+        MP_STATE_MEM(permanent_pointers) = next_block;
+    } else {
+        last_reference_block[0] = next_block;
+    }
+    next_block[1] = ptr;
+    return true;
+}
+
 void gc_dump_info(const mp_print_t *print) {
     gc_info_t info;
     gc_info(&info);
diff --git a/py/mkrules.mk b/py/mkrules.mk
index 421a0d1c59..0dd35573d0 100644
--- a/py/mkrules.mk
+++ b/py/mkrules.mk
@@ -78,7 +78,8 @@ $(Q)$(CXX) $(CXXFLAGS) -c -MD -o $@ $< || (echo -e $(HELP_BUILD_ERROR); false)
   $(RM) -f $(@:.o=.d)
 endef
 
-vpath %.c . $(TOP) $(USER_C_MODULES)
+# CIRCUITPY: add $(DEVICES_MODULES) and $(BUILD)
+vpath %.c . $(TOP) $(USER_C_MODULES) $(DEVICES_MODULES) $(BUILD)
 $(BUILD)/%.o: %.c
 	$(call compile_c)
 
diff --git a/py/obj.c b/py/obj.c
index 9c1cffc728..f8316ce5b2 100644
--- a/py/obj.c
+++ b/py/obj.c
@@ -640,6 +640,39 @@ mp_obj_t mp_identity(mp_obj_t self) {
 }
 MP_DEFINE_CONST_FUN_OBJ_1(mp_identity_obj, mp_identity);
 
+// CIRCUITPY
+// generic subscript iterator, which iterates through anything with a 0-based subscript.
+typedef struct {
+    mp_obj_base_t base;
+    mp_fun_1_t iternext;
+    mp_obj_t obj;
+    mp_int_t cur;
+} mp_obj_generic_subscript_it_t;
+
+STATIC mp_obj_t generic_subscript_it_iternext(mp_obj_t self_in) {
+    mp_obj_generic_subscript_it_t *self = MP_OBJ_TO_PTR(self_in);
+    const mp_obj_type_t *type = mp_obj_get_type(self->obj);
+    mp_obj_t current_length = MP_OBJ_TYPE_GET_SLOT(type, unary_op)(MP_UNARY_OP_LEN, self->obj);
+    if (self->cur < MP_OBJ_SMALL_INT_VALUE(current_length)) {
+        mp_obj_t o_out =
+            MP_OBJ_TYPE_GET_SLOT(type, subscr)(self->obj, MP_OBJ_NEW_SMALL_INT(self->cur), MP_OBJ_SENTINEL);
+        self->cur += 1;
+        return o_out;
+    } else {
+        return MP_OBJ_STOP_ITERATION;
+    }
+}
+
+mp_obj_t mp_obj_generic_subscript_getiter(mp_obj_t obj, mp_obj_iter_buf_t *iter_buf) {
+    assert(sizeof(mp_obj_generic_subscript_it_t) <= sizeof(mp_obj_iter_buf_t));
+    mp_obj_generic_subscript_it_t *o = (mp_obj_generic_subscript_it_t *)iter_buf;
+    o->base.type = &mp_type_polymorph_iter;
+    o->iternext = &generic_subscript_it_iternext;
+    o->obj = obj;
+    o->cur = 0;
+    return MP_OBJ_FROM_PTR(o);
+}
+
 // mp_obj_t mp_identity_getiter(mp_obj_t self, mp_obj_iter_buf_t *iter_buf) {
 //     (void)iter_buf;
 //     return self;
diff --git a/py/obj.h b/py/obj.h
index bb55ea3351..2576f87cf1 100644
--- a/py/obj.h
+++ b/py/obj.h
@@ -1251,7 +1251,7 @@ MP_DECLARE_CONST_FUN_OBJ_1(mp_identity_obj);
 
 // Generic iterator that uses unary op and subscr to iterate over a native type. It will be slower
 // than a custom iterator but applies broadly.
-mp_obj_t mp_obj_new_generic_iterator(mp_obj_t self, mp_obj_iter_buf_t *iter_buf);
+mp_obj_t mp_obj_generic_subscript_getiter(mp_obj_t self, mp_obj_iter_buf_t *iter_buf);
 
 // module
 typedef struct _mp_obj_module_t {
diff --git a/shared-bindings/adafruit_pixelbuf/PixelBuf.c b/shared-bindings/adafruit_pixelbuf/PixelBuf.c
index e7bde6f429..20455026b4 100644
--- a/shared-bindings/adafruit_pixelbuf/PixelBuf.c
+++ b/shared-bindings/adafruit_pixelbuf/PixelBuf.c
@@ -376,5 +376,5 @@ MP_DEFINE_CONST_OBJ_TYPE(
     make_new, pixelbuf_pixelbuf_make_new,
     subscr, pixelbuf_pixelbuf_subscr,
     unary_op, pixelbuf_pixelbuf_unary_op,
-    iter, mp_obj_new_generic_iterator
+    iter, mp_obj_generic_subscript_getiter
     );
diff --git a/shared-bindings/displayio/Group.c b/shared-bindings/displayio/Group.c
index 03ba3c4165..177d62f83a 100644
--- a/shared-bindings/displayio/Group.c
+++ b/shared-bindings/displayio/Group.c
@@ -356,5 +356,5 @@ MP_DEFINE_CONST_OBJ_TYPE(
     locals_dict, &displayio_group_locals_dict,
     subscr, group_subscr,
     unary_op, group_unary_op,
-    iter, mp_obj_new_generic_iterator
+    iter, mp_obj_generic_subscript_getiter
     );
diff --git a/shared-bindings/displayio/Palette.c b/shared-bindings/displayio/Palette.c
index dcf0f7bd9b..2c0e7ee3a1 100644
--- a/shared-bindings/displayio/Palette.c
+++ b/shared-bindings/displayio/Palette.c
@@ -223,6 +223,5 @@ MP_DEFINE_CONST_OBJ_TYPE(
     locals_dict, &displayio_palette_locals_dict,
     subscr, palette_subscr,
     unary_op, group_unary_op,
-    iter, mp_obj_new_generic_iterator
-
+    iter, mp_obj_generic_subscript_getiter
     );
diff --git a/shared-bindings/memorymonitor/AllocationSize.c b/shared-bindings/memorymonitor/AllocationSize.c
index 53ca66227d..117ad2a9d4 100644
--- a/shared-bindings/memorymonitor/AllocationSize.c
+++ b/shared-bindings/memorymonitor/AllocationSize.c
@@ -171,6 +171,6 @@ MP_DEFINE_CONST_OBJ_TYPE(
     make_new, memorymonitor_allocationsize_make_new,
     subscr, memorymonitor_allocationsize_subscr,
     unary_op, memorymonitor_allocationsize_unary_op,
-    getiter, mp_obj_new_generic_iterator,
+    iter, mp_obj_generic_subscript_getiter,
     locals_dict, &memorymonitor_allocationsize_locals_dict
     );