diff --git a/tools/generate-wire.py b/tools/generate-wire.py
index f3765f0a0..131de5c46 100755
--- a/tools/generate-wire.py
+++ b/tools/generate-wire.py
@@ -169,7 +169,9 @@ class Field(object):
 
         # Bolts use just a number: Guess type based on size.
         if options.bolt:
-            if size == 'var_int':
+            if size == '$':  # this is a subtype
+                self.fieldtype = FieldType('struct {}'.format(name))
+            elif size == 'var_int':
                 base_size = 8
                 self.fieldtype = FieldType(size)
             else:
@@ -853,6 +855,14 @@ struct {struct_name} {{
             fields=str(fmt_fields))
 
 
+class Subtype(Message):
+    def __init__(self, name, comments):
+        super().__init__(name, None, comments, False)
+
+    def print_struct(self):
+        return TlvMessage._inner_print_struct(self.name, self.fields)
+
+
 tlv_message_towire_stub = """static void towire_{tlv_name}_{name}(u8 **p, struct tlv_msg_{name} *{name}) {{
 {field_decls}
 {subcalls}
@@ -1071,6 +1081,7 @@ options = parser.parse_args()
 # Maps message names to messages
 messages = []
 messages_with_option = []
+subtypes = []
 comments = []
 includes = []
 tlv_fields = {}
@@ -1096,18 +1107,21 @@ for line in fileinput.input(options.files):
     is_tlv_msg = len(parts) == 3
     if len(parts) == 2 or is_tlv_msg:
         # eg: commit_sig,132,(_tlv)
-        if is_tlv_msg:
-            message = TlvMessage(parts[0],
-                                 Enumtype("WIRE_" + parts[0].upper(), parts[1]),
-                                 comments)
+        if parts[1] == '$':  # this is a subtype
+            subtypes.append(Subtype(parts[0], comments))
         else:
-            message = Message(parts[0],
-                              Enumtype("WIRE_" + parts[0].upper(), parts[1]),
-                              comments)
+            if is_tlv_msg:
+                message = TlvMessage(parts[0],
+                                     Enumtype("WIRE_" + parts[0].upper(), parts[1]),
+                                     comments)
+            else:
+                message = Message(parts[0],
+                                  Enumtype("WIRE_" + parts[0].upper(), parts[1]),
+                                  comments)
 
-        messages.append(message)
-        if is_tlv_msg:
-            tlv_fields[parts[2]].append(message)
+            messages.append(message)
+            if is_tlv_msg:
+                tlv_fields[parts[2]].append(message)
 
         comments = []
         prevfield = None
@@ -1115,9 +1129,9 @@ for line in fileinput.input(options.files):
         if len(parts) == 4:
             # eg commit_sig,0,channel-id,8 OR
             #    commit_sig,0,channel-id,u64
-            m = find_message(messages, parts[0])
+            m = find_message(messages + subtypes, parts[0])
             if m is None:
-                raise ValueError('Unknown message {}'.format(parts[0]))
+                raise ValueError('Unknown message or subtype {}'.format(parts[0]))
         elif len(parts) == 5:
             # eg.
             # channel_reestablish,48,your_last_per_commitment_secret,32,option209
@@ -1187,6 +1201,13 @@ def build_tlv_structs(tlv_fields):
     return structs
 
 
+def build_subtype_structs(subtypes):
+    structs = ""
+    for subtype in subtypes:
+        structs += subtype.print_struct()
+    return structs
+
+
 enum_header_template = """enum {enumname} {{
 {enums}
 }};
@@ -1214,7 +1235,7 @@ header_template = """/* This file was generated by generate-wire.py */
 #include <ccan/tal/tal.h>
 #include <wire/wire.h>
 {includes}
-{formatted_hdr_enums}{tlv_structs}
+{formatted_hdr_enums}{gen_structs}
 {func_decls}
 #endif /* LIGHTNING_{idem} */
 """
@@ -1304,6 +1325,7 @@ built_hdr_enums = build_hdr_enums(options.enumname, toplevel_messages, tlv_field
 built_impl_enums = build_impl_enums(options.enumname, toplevel_messages, tlv_fields)
 tlv_structs = build_tlv_structs(tlv_fields)
 tlv_structs += build_tlv_type_structs(tlv_fields)
+subtype_structs = build_subtype_structs(subtypes)
 includes = '\n'.join(includes)
 printcases = ['case {enum.name}: printf("{enum.name}:\\n"); printwire_{name}("{name}", msg); return;'.format(enum=m.enum, name=m.name) for m in toplevel_messages]
 
@@ -1339,5 +1361,5 @@ print(template.format(
     enumname=options.enumname,
     formatted_hdr_enums=built_hdr_enums,
     formatted_impl_enums=built_impl_enums,
-    tlv_structs=tlv_structs,
+    gen_structs=tlv_structs + subtype_structs,
     func_decls='\n'.join(decls)))