diff --git a/src/c3nav/mesh/management/commands/set_node_number.py b/src/c3nav/mesh/management/commands/set_node_number.py
new file mode 100644
index 00000000..41f768b4
--- /dev/null
+++ b/src/c3nav/mesh/management/commands/set_node_number.py
@@ -0,0 +1,116 @@
+from dataclasses import fields
+
+from django.core.management.base import BaseCommand
+
+from c3nav.mesh.baseformats import StructType, normalize_name
+from c3nav.mesh.messages import MeshMessage
+from c3nav.mesh.utils import indent_c
+
+
+class Command(BaseCommand):
+    help = 'export mesh message structs for c code'
+
+    def handle(self,  *args, **options):
+        done_struct_names = set()
+        nodata = set()
+        struct_lines = {}
+        struct_sizes = []
+        struct_max_sizes = []
+        done_definitions = set()
+
+        for include in StructType.c_includes:
+            print(f'#include {include}')
+
+        ignore_names = set(field_.name for field_ in fields(MeshMessage))
+        for msg_type, msg_class in MeshMessage.get_types().items():
+            if msg_class.c_struct_name:
+                if msg_class.c_struct_name in done_struct_names:
+                    continue
+                done_struct_names.add(msg_class.c_struct_name)
+                if MeshMessage.c_structs[msg_class.c_struct_name] != msg_class:
+                    # the purpose of MeshMessage.c_structs is unclear, currently this never triggers
+                    # todo get rid of the whole c_structs thing if it doesn't turn out to be useful for anything
+                    raise ValueError('what happened?')
+
+            base_name = (msg_class.c_struct_name or normalize_name(
+                getattr(msg_type, 'name', msg_class.__name__)
+            ))
+            name = "mesh_msg_%s_t" % base_name
+
+            for definition_name, definition in msg_class.get_c_definitions().items():
+                if definition_name not in done_definitions:
+                    done_definitions.add(definition_name)
+                    print(definition)
+                    print()
+
+            code = msg_class.get_c_code(name, ignore_fields=ignore_names, no_empty=True)
+            if code:
+                size = msg_class.get_size(no_inherited_fields=True, calculate_max=False)
+                max_size = msg_class.get_size(no_inherited_fields=True, calculate_max=True)
+                struct_lines[base_name] = "%s %s;" % (name, base_name.replace('_announce', ''))
+                struct_sizes.append(size)
+                struct_max_sizes.append(max_size)
+                print(code)
+                print("static_assert(sizeof(%s) == %d, \"size of generated message structs is calculated wrong\");" %
+                      (name, size))
+                print()
+            else:
+                nodata.add(msg_class)
+
+        print("/** union between all message data structs */")
+        print("typedef union __packed {")
+        for line in struct_lines.values():
+            print(indent_c(line))
+        print("} mesh_msg_data_t; ")
+        print(
+            "static_assert(sizeof(mesh_msg_data_t) == %d, \"size of generated message structs is calculated wrong\");"
+            % max(struct_sizes)
+        )
+
+        print()
+        print('#define MESH_MSG_MAX_LENGTH (%d)' % max(struct_max_sizes))
+
+        print()
+
+        max_msg_type = max(MeshMessage.get_types().keys())
+        macro_data = []
+        for i in range(((max_msg_type//16)+1)*16):
+            msg_class = MeshMessage.get_types().get(i, None)
+            if msg_class:
+                name = (msg_class.c_struct_name or normalize_name(
+                    getattr(msg_class.msg_type, 'name', msg_class.__name__)
+                ))
+                macro_data.append((
+                    msg_class.get_c_enum_name(),
+                    ("nodata" if msg_class in nodata else name),
+                    msg_class.get_var_num(),
+                    msg_class.get_size(no_inherited_fields=True, calculate_max=True),
+                    msg_class.__doc__.strip(),
+                ))
+            else:
+                macro_data.append((
+                    "RESERVED_%02X" % i,
+                    "nodata",
+                    0,
+                    0,
+                    "",
+                ))
+
+        max0 = max(len(d[0]) for d in macro_data)
+        max1 = max(len(d[1]) for d in macro_data)
+        max2 = max(len(str(d[2])) for d in macro_data)
+        max3 = max(len(str(d[3])) for d in macro_data)
+        lines = []
+        for i, (macro_name, struct_name, num_len, max_len, comment) in enumerate(macro_data):
+            lines.append(indent_c(
+                "FN(%s %s %s %s)  /** 0x%02X %s*/" % (
+                    f'{macro_name},'.ljust(max0+1),
+                    f'{struct_name},'.ljust(max1+1),
+                    f'{num_len},'.rjust(max2+1),
+                    f'{max_len}'.rjust(max3),
+                    i,
+                    comment+(" " if comment else ""),
+                )
+            ))
+        print("#define FOR_ALL_MESH_MSG_TYPES(FN)  \\")
+        print("  \\\n".join(lines))
diff --git a/src/c3nav/mesh/messages.py b/src/c3nav/mesh/messages.py
index e2c8959b..aee537a7 100644
--- a/src/c3nav/mesh/messages.py
+++ b/src/c3nav/mesh/messages.py
@@ -337,7 +337,7 @@ class OTAFragmentMessage(MeshMessage, msg_type=MeshMessageType.OTA_FRAGMENT):
 class OTARequestFragmentsMessage(MeshMessage, msg_type=MeshMessageType.OTA_REQUEST_FRAGMENTS):
     """ request missing fragments """
     update_id: int = field(metadata={"format": SimpleFormat('I')})
-    chunks: list[int] = field(metadata={"format": VarArrayFormat(SimpleFormat('H'), max_num=32)})
+    chunks: list[int] = field(metadata={"format": VarArrayFormat(SimpleFormat('H'), max_num=128)})
 
 
 @dataclass