diff --git a/py/binary.c b/py/binary.c
index 846058525f..cd61d74fa8 100644
--- a/py/binary.c
+++ b/py/binary.c
@@ -371,11 +371,7 @@ void mp_binary_set_val(char struct_type, char val_type, mp_obj_t val_in, byte **
         }
     }
 
-    if (val_type == 'x') {
-        memset(p, 0, 1);
-    } else {
-        mp_binary_set_int(MIN((size_t)size, sizeof(val)), struct_type == '>', p, val);
-    }
+    mp_binary_set_int(MIN((size_t)size, sizeof(val)), struct_type == '>', p, val);
 }
 
 void mp_binary_set_val_array(char typecode, void *p, mp_uint_t index, mp_obj_t val_in) {
diff --git a/py/modstruct.c b/py/modstruct.c
index 1c5319608d..8f78fa234a 100644
--- a/py/modstruct.c
+++ b/py/modstruct.c
@@ -214,9 +214,11 @@ STATIC void struct_pack_into_internal(mp_obj_t fmt_in, byte *p, size_t n_args, c
             p += cnt;
         } else {
             while (cnt--) {
-                mp_binary_set_val(fmt_type, *fmt, args[i], &p);
                 // Pad bytes don't have a corresponding argument.
-                if (*fmt != 'x') {
+                if (*fmt == 'x') {
+                    mp_binary_set_val(fmt_type, *fmt, MP_OBJ_NEW_SMALL_INT(0), &p);
+                } else {
+                    mp_binary_set_val(fmt_type, *fmt, args[i], &p);
                     i++;
                 }
             }
diff --git a/shared-module/struct/__init__.c b/shared-module/struct/__init__.c
index 7a7ea845e7..258036c93b 100644
--- a/shared-module/struct/__init__.c
+++ b/shared-module/struct/__init__.c
@@ -153,9 +153,11 @@ void shared_modules_struct_pack_into(mp_obj_t fmt_in, byte *p, byte *end_p, size
             p += sz;
         } else {
             while (sz--) {
-                mp_binary_set_val(fmt_type, *fmt, args[i], &p);
                 // Pad bytes don't have a corresponding argument.
-                if (*fmt != 'x') {
+                if (*fmt == 'x') {
+                    mp_binary_set_val(fmt_type, *fmt, MP_OBJ_NEW_SMALL_INT(0), &p);
+                } else {
+                    mp_binary_set_val(fmt_type, *fmt, args[i], &p);
                     i++;
                 }
             }
diff --git a/tests/basics/struct1.py b/tests/basics/struct1.py
index 107006cc3f..ec29ea9080 100644
--- a/tests/basics/struct1.py
+++ b/tests/basics/struct1.py
@@ -121,3 +121,5 @@ except:
 
 # check padding bytes
 print(struct.pack("xb", 3))
+# Make sure pack doesn't reuse a larger value and error
+print(struct.pack("xH", 0x100))