diff --git a/qemu-arm/mpconfigport.h b/qemu-arm/mpconfigport.h
index a9f98e5ce2..38ea2f7c3e 100644
--- a/qemu-arm/mpconfigport.h
+++ b/qemu-arm/mpconfigport.h
@@ -19,6 +19,7 @@
 #define MICROPY_PY_BUILTINS_MEMORYVIEW (1)
 #define MICROPY_PY_IO               (0)
 #define MICROPY_PY_SYS_EXIT         (1)
+#define MICROPY_PY_SYS_MAXSIZE      (1)
 
 // type definitions for the specific machine
 
@@ -26,6 +27,8 @@
 
 #define MICROPY_MAKE_POINTER_CALLABLE(p) ((void*)((mp_uint_t)(p) | 1))
 
+#define MP_SSIZE_MAX (0x7fffffff)
+
 #define UINT_FMT "%lu"
 #define INT_FMT "%ld"
 
diff --git a/stmhal/mpconfigport.h b/stmhal/mpconfigport.h
index bfb3661eac..07db263d5e 100644
--- a/stmhal/mpconfigport.h
+++ b/stmhal/mpconfigport.h
@@ -64,6 +64,7 @@
 #define MICROPY_PY_MICROPYTHON_MEM_INFO (1)
 #define MICROPY_PY_ARRAY_SLICE_ASSIGN (1)
 #define MICROPY_PY_SYS_EXIT         (1)
+#define MICROPY_PY_SYS_MAXSIZE      (1)
 #define MICROPY_PY_SYS_STDFILES     (1)
 #define MICROPY_PY_COLLECTIONS_ORDEREDDICT (1)
 #define MICROPY_PY_MATH_SPECIAL_FUNCTIONS (1)
@@ -171,6 +172,8 @@ extern const struct _mp_obj_module_t mp_module_network;
 
 #define MICROPY_MAKE_POINTER_CALLABLE(p) ((void*)((mp_uint_t)(p) | 1))
 
+#define MP_SSIZE_MAX (0x7fffffff)
+
 #define UINT_FMT "%u"
 #define INT_FMT "%d"