diff --git a/ports/atmel-samd/mpconfigport.h b/ports/atmel-samd/mpconfigport.h
index 1ce44ac8af..a5884b6ad9 100644
--- a/ports/atmel-samd/mpconfigport.h
+++ b/ports/atmel-samd/mpconfigport.h
@@ -46,6 +46,7 @@
 #define MICROPY_PY_BUILTINS_SLICE   (1)
 #define MICROPY_PY_BUILTINS_SLICE_ATTRS (1)
 #define MICROPY_PY_ARRAY_SLICE_ASSIGN (1)
+#define MICROPY_NONSTANDARD_TYPECODES (0)
 #define MICROPY_PY_BUILTINS_PROPERTY (1)
 #define MICROPY_PY_BUILTINS_MIN_MAX (1)
 #define MICROPY_PY___FILE__         (1)
diff --git a/ports/esp8266/mpconfigport.h b/ports/esp8266/mpconfigport.h
index cdf06450c6..8caecf7594 100644
--- a/ports/esp8266/mpconfigport.h
+++ b/ports/esp8266/mpconfigport.h
@@ -49,6 +49,7 @@
 #define MICROPY_PY_GC               (1)
 #define MICROPY_PY_ARRAY            (1)
 #define MICROPY_PY_ARRAY_SLICE_ASSIGN (1)
+#define MICROPY_NONSTANDARD_TYPECODES (0)
 #define MICROPY_PY_COLLECTIONS      (1)
 #define MICROPY_PY_COLLECTIONS_ORDEREDDICT (1)
 #define MICROPY_PY_MATH             (0)
diff --git a/ports/nrf/mpconfigport.h b/ports/nrf/mpconfigport.h
index 053a3bbab2..e806c201f1 100644
--- a/ports/nrf/mpconfigport.h
+++ b/ports/nrf/mpconfigport.h
@@ -99,6 +99,7 @@
 #define MICROPY_PY_ALL_SPECIAL_METHODS           (0)
 #define MICROPY_PY_MICROPYTHON_MEM_INFO          (1)
 #define MICROPY_PY_ARRAY_SLICE_ASSIGN            (0)
+#define MICROPY_NONSTANDARD_TYPECODES            (0)
 #define MICROPY_PY_BUILTINS_SLICE_ATTRS          (0)
 #define MICROPY_PY_SYS_EXIT                      (1)
 #define MICROPY_PY_SYS_MAXSIZE                   (1)
diff --git a/py/binary.c b/py/binary.c
index 62cb384f18..bb334ed3db 100644
--- a/py/binary.c
+++ b/py/binary.c
@@ -57,8 +57,10 @@ size_t mp_binary_get_size(char struct_type, char val_type, mp_uint_t *palign) {
                     size = 4; break;
                 case 'q': case 'Q':
                     size = 8; break;
+#if MICROPY_NONSTANDARD_TYPECODES
                 case 'P': case 'O': case 'S':
                     size = sizeof(void*); break;
+#endif
                 case 'f':
                     size = sizeof(float); break;
                 case 'd':
@@ -89,9 +91,11 @@ size_t mp_binary_get_size(char struct_type, char val_type, mp_uint_t *palign) {
                 case 'q': case 'Q':
                     align = alignof(long long);
                     size = sizeof(long long); break;
+#if MICROPY_NONSTANDARD_TYPECODES
                 case 'P': case 'O': case 'S':
                     align = alignof(void*);
                     size = sizeof(void*); break;
+#endif
                 case 'f':
                     align = alignof(float);
                     size = sizeof(float); break;
@@ -148,12 +152,14 @@ mp_obj_t mp_binary_get_val_array(char typecode, void *p, mp_uint_t index) {
         case 'd':
             return mp_obj_new_float(((double*)p)[index]);
 #endif
+#if MICROPY_NONSTANDARD_TYPECODES
         // Extension to CPython: array of objects
         case 'O':
             return ((mp_obj_t*)p)[index];
         // Extension to CPython: array of pointers
         case 'P':
             return mp_obj_new_int((mp_int_t)(uintptr_t)((void**)p)[index]);
+#endif
     }
     return MP_OBJ_NEW_SMALL_INT(val);
 }
@@ -202,11 +208,13 @@ mp_obj_t mp_binary_get_val(char struct_type, char val_type, byte **ptr) {
 
     long long val = mp_binary_get_int(size, is_signed(val_type), (struct_type == '>'), p);
 
-    if (val_type == 'O') {
+    if (MICROPY_NONSTANDARD_TYPECODES && (val_type == 'O')) {
         return (mp_obj_t)(mp_uint_t)val;
+#if MICROPY_NONSTANDARD_TYPECODES
     } else if (val_type == 'S') {
         const char *s_val = (const char*)(uintptr_t)(mp_uint_t)val;
         return mp_obj_new_str(s_val, strlen(s_val), false);
+#endif
 #if MICROPY_PY_BUILTINS_FLOAT
     } else if (val_type == 'f') {
         union { uint32_t i; float f; } fpu = {val};
@@ -267,9 +275,11 @@ void mp_binary_set_val(char struct_type, char val_type, mp_obj_t val_in, byte **
 
     mp_uint_t val;
     switch (val_type) {
+#if MICROPY_NONSTANDARD_TYPECODES
         case 'O':
             val = (mp_uint_t)val_in;
             break;
+#endif
 #if MICROPY_PY_BUILTINS_FLOAT
         case 'f': {
             union { uint32_t i; float f; } fp_sp;
@@ -324,10 +334,12 @@ void mp_binary_set_val_array(char typecode, void *p, mp_uint_t index, mp_obj_t v
             ((double*)p)[index] = mp_obj_get_float(val_in);
             break;
 #endif
+#if MICROPY_NONSTANDARD_TYPECODES
         // Extension to CPython: array of objects
         case 'O':
             ((mp_obj_t*)p)[index] = val_in;
             break;
+#endif
         default:
             #if MICROPY_LONGINT_IMPL != MICROPY_LONGINT_IMPL_NONE
             if (MP_OBJ_IS_TYPE(val_in, &mp_type_int)) {
@@ -384,9 +396,11 @@ void mp_binary_set_val_array_from_int(char typecode, void *p, mp_uint_t index, m
             ((double*)p)[index] = val;
             break;
 #endif
+#if MICROPY_NONSTANDARD_TYPECODES
         // Extension to CPython: array of pointers
         case 'P':
             ((void**)p)[index] = (void*)(uintptr_t)val;
             break;
+#endif
     }
 }
diff --git a/py/mpconfig.h b/py/mpconfig.h
index 252ab7f371..765ae1e8f0 100644
--- a/py/mpconfig.h
+++ b/py/mpconfig.h
@@ -888,6 +888,12 @@ typedef double mp_float_t;
 #define MICROPY_PY_ARRAY_SLICE_ASSIGN (0)
 #endif
 
+// Whether to support nonstandard typecodes "O", "P" and "S"
+// in array and struct modules.
+#ifndef MICROPY_NONSTANDARD_TYPECODES
+#define MICROPY_NONSTANDARD_TYPECODES (1)
+#endif
+
 // Whether to support attrtuple type (MicroPython extension)
 // It provides space-efficient tuples with attribute access
 #ifndef MICROPY_PY_ATTRTUPLE
diff --git a/py/objarray.c b/py/objarray.c
index eb053bd8a9..c4c547e19f 100644
--- a/py/objarray.c
+++ b/py/objarray.c
@@ -470,9 +470,11 @@ STATIC mp_obj_t array_subscr(mp_obj_t self_in, mp_obj_t index_in, mp_obj_t value
                 } else {
                     mp_seq_replace_slice_no_grow(dest_items, o->len,
                         slice.start, slice.stop, src_items, src_len, item_sz);
+#if MICROPY_NONSTANDARD_TYPECODES
                     // Clear "freed" elements at the end of list
                     // TODO: This is actually only needed for typecode=='O'
                     mp_seq_clear(dest_items, o->len + len_adj, o->len, item_sz);
+#endif
                     // TODO: alloc policy after shrinking
                 }
                 o->len += len_adj;
diff --git a/shared-module/struct/__init__.c b/shared-module/struct/__init__.c
index e944f77387..eac41c9c31 100644
--- a/shared-module/struct/__init__.c
+++ b/shared-module/struct/__init__.c
@@ -33,9 +33,11 @@
 #include "py/parsenum.h"
 
 void struct_validate_format(char fmt) {
+#if MICROPY_NONSTANDARD_TYPECODES
     if( fmt == 'S' || fmt == 'O') {
         mp_raise_RuntimeError("'S' and 'O' are not supported format types");
     }
+#endif
 }
 
 char get_fmt_type(const char **fmt) {
diff --git a/tests/basics/array_micropython.py b/tests/basics/array_micropython.py
index e26ad7ae96..b92c5a9b93 100644
--- a/tests/basics/array_micropython.py
+++ b/tests/basics/array_micropython.py
@@ -5,6 +5,12 @@ except ImportError:
     print("SKIP")
     raise SystemExit
 
+try:
+    array.array('O')
+except ValueError:
+    print("SKIP")
+    raise SystemExit
+
 # arrays of objects
 a = array.array('O')
 a.append(1)
diff --git a/tests/basics/struct_micropython.py b/tests/basics/struct_micropython.py
index f203a4666f..e721530714 100644
--- a/tests/basics/struct_micropython.py
+++ b/tests/basics/struct_micropython.py
@@ -9,6 +9,12 @@ except:
         print("SKIP")
         raise SystemExit
 
+try:
+    struct.pack('O', None)
+except ValueError:
+    print("SKIP")
+    raise SystemExit
+
 class A():
     pass