diff --git a/extmod/moductypes.c b/extmod/moductypes.c
index dff8abd8d..56da80931 100644
--- a/extmod/moductypes.c
+++ b/extmod/moductypes.c
@@ -122,14 +122,11 @@ STATIC NORETURN void syntax_error(void) {
 }
 
 STATIC mp_obj_t uctypes_struct_make_new(mp_obj_t type_in, mp_uint_t n_args, mp_uint_t n_kw, const mp_obj_t *args) {
-    (void)n_kw;
-    if (n_args < 2 || n_args > 3) {
-        syntax_error();
-    }
+    mp_arg_check_num(n_args, n_kw, 2, 3, false);
     mp_obj_uctypes_struct_t *o = m_new_obj(mp_obj_uctypes_struct_t);
     o->base.type = type_in;
-    o->desc = args[0];
-    o->addr = (void*)mp_obj_get_int(args[1]);
+    o->addr = (void*)mp_obj_get_int(args[0]);
+    o->desc = args[1];
     o->flags = LAYOUT_NATIVE;
     if (n_args == 3) {
         o->flags = mp_obj_get_int(args[2]);
diff --git a/tests/extmod/uctypes_bytearray.py b/tests/extmod/uctypes_bytearray.py
index 9f3d7ca8b..7294b7ea4 100644
--- a/tests/extmod/uctypes_bytearray.py
+++ b/tests/extmod/uctypes_bytearray.py
@@ -7,7 +7,7 @@ desc = {
 
 data = bytearray(b"01234567")
 
-S = uctypes.struct(desc, uctypes.addressof(data), uctypes.LITTLE_ENDIAN)
+S = uctypes.struct(uctypes.addressof(data), desc, uctypes.LITTLE_ENDIAN)
 
 # Arrays of UINT8 are accessed as bytearrays
 print(S.arr)
diff --git a/tests/extmod/uctypes_le.py b/tests/extmod/uctypes_le.py
index 416a00744..ff499476f 100644
--- a/tests/extmod/uctypes_le.py
+++ b/tests/extmod/uctypes_le.py
@@ -22,7 +22,7 @@ desc = {
 
 data = bytearray(b"01")
 
-S = uctypes.struct(desc, uctypes.addressof(data), uctypes.LITTLE_ENDIAN)
+S = uctypes.struct(uctypes.addressof(data), desc, uctypes.LITTLE_ENDIAN)
 
 #print(S)
 print(hex(S.s0))
diff --git a/tests/extmod/uctypes_native_le.py b/tests/extmod/uctypes_native_le.py
index b4694994a..a053b68d5 100644
--- a/tests/extmod/uctypes_native_le.py
+++ b/tests/extmod/uctypes_native_le.py
@@ -31,7 +31,7 @@ desc = {
 
 data = bytearray(b"01")
 
-S = uctypes.struct(desc, uctypes.addressof(data), uctypes.NATIVE)
+S = uctypes.struct(uctypes.addressof(data), desc, uctypes.NATIVE)
 
 #print(S)
 print(hex(S.s0))
diff --git a/tests/extmod/uctypes_ptr_le.py b/tests/extmod/uctypes_ptr_le.py
index 411799db5..4bff58517 100644
--- a/tests/extmod/uctypes_ptr_le.py
+++ b/tests/extmod/uctypes_ptr_le.py
@@ -16,7 +16,7 @@ bytes = b"01"
 addr = uctypes.addressof(bytes)
 buf = addr.to_bytes(uctypes.sizeof(desc))
 
-S = uctypes.struct(desc, uctypes.addressof(buf), uctypes.LITTLE_ENDIAN)
+S = uctypes.struct(uctypes.addressof(buf), desc, uctypes.LITTLE_ENDIAN)
 
 print(S.ptr[0])
 assert S.ptr[0] == ord("0")
diff --git a/tests/extmod/uctypes_ptr_native_le.py b/tests/extmod/uctypes_ptr_native_le.py
index ba06b2650..0d02cfdc8 100644
--- a/tests/extmod/uctypes_ptr_native_le.py
+++ b/tests/extmod/uctypes_ptr_native_le.py
@@ -17,7 +17,7 @@ bytes = b"01"
 addr = uctypes.addressof(bytes)
 buf = addr.to_bytes(uctypes.sizeof(desc))
 
-S = uctypes.struct(desc, uctypes.addressof(buf), uctypes.NATIVE)
+S = uctypes.struct(uctypes.addressof(buf), desc, uctypes.NATIVE)
 
 print(S.ptr[0])
 assert S.ptr[0] == ord("0")
diff --git a/tests/extmod/uctypes_sizeof.py b/tests/extmod/uctypes_sizeof.py
index f6551a738..2f2a0c0d0 100644
--- a/tests/extmod/uctypes_sizeof.py
+++ b/tests/extmod/uctypes_sizeof.py
@@ -10,7 +10,7 @@ desc = {
 
 data = bytearray(b"01234567")
 
-S = uctypes.struct(desc, uctypes.addressof(data), uctypes.LITTLE_ENDIAN)
+S = uctypes.struct(uctypes.addressof(data), desc, uctypes.LITTLE_ENDIAN)
 
 print(uctypes.sizeof(S.arr))
 assert uctypes.sizeof(S.arr) == 2
diff --git a/tests/extmod/uctypes_sizeof_native.py b/tests/extmod/uctypes_sizeof_native.py
index 0dfbfa980..f830a1f85 100644
--- a/tests/extmod/uctypes_sizeof_native.py
+++ b/tests/extmod/uctypes_sizeof_native.py
@@ -32,7 +32,7 @@ S5 = {
 
 assert uctypes.sizeof(S5) == 12
 
-s5 = uctypes.struct(S5, 0)
+s5 = uctypes.struct(0, S5)
 assert uctypes.sizeof(s5) == 12
 assert uctypes.sizeof(s5.sub) == 2