diff --git a/src/c3nav/mesh/baseformats.py b/src/c3nav/mesh/baseformats.py
new file mode 100644
index 00000000..312dcfe0
--- /dev/null
+++ b/src/c3nav/mesh/baseformats.py
@@ -0,0 +1,477 @@
+import re
+import struct
+from abc import ABC, abstractmethod
+from dataclasses import dataclass, fields, field, Field
+from typing import Any, Sequence, Self
+
+from c3nav.mesh.utils import indent_c
+
+
+class BaseFormat(ABC):
+
+
+    def get_var_num(self):
+        return 0
+
+    @abstractmethod
+    def encode(self, value):
+        pass
+
+    @classmethod
+    @abstractmethod
+    def decode(cls, data) -> tuple[Any, bytes]:
+        pass
+
+    def fromjson(self, data):
+        return data
+
+    def tojson(self, data):
+        return data
+
+    @abstractmethod
+    def get_min_size(self):
+        pass
+
+    @abstractmethod
+    def get_c_parts(self) -> tuple[str, str]:
+        pass
+
+    def get_c_code(self, name) -> str:
+        pre, post = self.get_c_parts()
+        return "%s %s%s;" % (pre, name, post)
+
+
+class SimpleFormat(BaseFormat):
+    def __init__(self, fmt):
+        self.fmt = fmt
+        self.size = struct.calcsize(fmt)
+
+        self.c_type = self.c_types[self.fmt[-1]]
+        self.num = int(self.fmt[:-1]) if len(self.fmt) > 1 else 1
+
+    def encode(self, value):
+        return struct.pack(self.fmt, (value,) if self.num == 1 else tuple(value))
+
+    def decode(self, data: bytes) -> tuple[Any, bytes]:
+        value = struct.unpack(self.fmt, data[:self.size])
+        if len(value) == 1:
+            value = value[0]
+        return value, data[self.size:]
+
+    def get_min_size(self):
+        return self.size
+
+    c_types = {
+        "B": "uint8_t",
+        "H": "uint16_t",
+        "I": "uint32_t",
+        "b": "int8_t",
+        "h": "int16_t",
+        "i": "int32_t",
+        "s": "char",
+    }
+
+    def get_c_parts(self):
+        return self.c_type, ("" if self.num == 1 else ("[%d]" % self.num))
+
+
+class BoolFormat(SimpleFormat):
+    def __init__(self):
+        super().__init__('B')
+
+    def encode(self, value):
+        return super().encode(int(value))
+
+    def decode(self, data: bytes) -> tuple[bool, bytes]:
+        value, data = super().decode(data)
+        return bool(value), data
+
+
+class FixedStrFormat(SimpleFormat):
+    def __init__(self, num):
+        self.num = num
+        super().__init__('%ds' % self.num)
+
+    def encode(self, value: str):
+        return value.encode()[:self.num].ljust(self.num, bytes((0,))),
+
+    def decode(self, data: bytes) -> tuple[str, bytes]:
+        return data[:self.num].rstrip(bytes((0,))).decode(), data[self.num:]
+
+
+class FixedHexFormat(SimpleFormat):
+    def __init__(self, num, sep=''):
+        self.num = num
+        self.sep = sep
+        super().__init__('%dB' % self.num)
+
+    def encode(self, value: str):
+        return super().encode(tuple(bytes.fromhex(value)))
+
+    def decode(self, data: bytes) -> tuple[str, bytes]:
+        return self.sep.join(('%02x' % i) for i in data[:self.num]), data[self.num:]
+
+
+@abstractmethod
+class BaseVarFormat(BaseFormat, ABC):
+    def __init__(self, num_fmt='B'):
+        self.num_fmt = num_fmt
+        self.num_size = struct.calcsize(self.num_fmt)
+
+    def get_min_size(self):
+        return self.num_size
+
+    def get_num_c_code(self):
+        return SimpleFormat(self.num_fmt).get_c_code("num")
+
+
+class VarArrayFormat(BaseVarFormat):
+    def __init__(self, child_type, num_fmt='B'):
+        super().__init__(num_fmt=num_fmt)
+        self.child_type = child_type
+        self.child_size = self.child_type.get_min_size()
+
+    def get_var_num(self):
+        return self.child_size
+        pass
+
+    def encode(self, values: Sequence) -> bytes:
+        data = struct.pack(self.num_fmt, (len(values),))
+        for value in values:
+            data += self.child_type.encode(value)
+        return data
+
+    def decode(self, data: bytes) -> tuple[list[Any], bytes]:
+        num = struct.unpack(self.num_fmt, data[:self.num_size])[0]
+        return [
+            self.child_type.decode(data[i:i + self.child_size])
+            for i in range(self.num_size, self.num_size + num * self.child_size, self.child_size)
+        ], data[self.num_size + num * self.child_size:]
+
+    def get_c_parts(self):
+        pre, post = self.child_type.get_c_parts()
+        return super().get_num_c_code() + "\n" + pre, "[0]" + post
+
+
+class VarStrFormat(BaseVarFormat):
+
+    def get_var_num(self):
+        return 1
+
+    def encode(self, value: str) -> bytes:
+        return struct.pack(self.num_fmt, (len(str),)) + value.encode()
+
+    def decode(self, data: bytes) -> tuple[str, bytes]:
+        num = struct.unpack(self.num_fmt, data[:self.num_size])[0]
+        return data[self.num_size:self.num_size + num].rstrip(bytes((0,))).decode(), data[self.num_size + num:]
+
+    def get_c_parts(self):
+        return super().get_num_c_code() + "\n" + "char", "[0]"
+
+
+@dataclass
+class StructType:
+    _union_options = {}
+    union_type_field = None
+
+    # noinspection PyMethodOverriding
+    def __init_subclass__(cls, /, union_type_field=None, no_c_type=False, **kwargs):
+        cls.union_type_field = union_type_field
+        if union_type_field:
+            if union_type_field in cls._union_options:
+                raise TypeError('Duplicate union_type_field: %s', union_type_field)
+            cls._union_options[union_type_field] = {}
+            f = getattr(cls, union_type_field)
+            metadata = dict(f.metadata)
+            metadata['union_discriminator'] = True
+            f.metadata = metadata
+            f.repr = False
+            f.init = False
+
+        for attr_name in cls.__dict__.keys():
+            attr = getattr(cls, attr_name)
+            if isinstance(attr, Field):
+                metadata = dict(attr.metadata)
+                if "defining_class" not in metadata:
+                    metadata["defining_class"] = cls
+                attr.metadata = metadata
+
+        for key, values in cls._union_options.items():
+            value = kwargs.pop(key, None)
+            if value is not None:
+                if value in values:
+                    raise TypeError('Duplicate %s: %s', (key, value))
+                values[value] = cls
+                setattr(cls, key, value)
+        super().__init_subclass__(**kwargs)
+
+    @classmethod
+    def get_var_num(cls):
+        return sum([f.metadata.get("format", f.type).get_var_num() for f in fields(cls)], start=0)
+
+    @classmethod
+    def encode(cls, instance) -> bytes:
+        data = bytes()
+        if cls.union_type_field and type(instance) is not cls:
+            if not isinstance(instance, cls):
+                raise ValueError('expected value of type %r, got %r' % (cls, instance))
+
+            for field_ in fields(instance):
+                if field_.name is cls.union_type_field:
+                    data += field_.metadata["format"].encode(getattr(instance, field_.name))
+                    break
+            else:
+                raise TypeError('couldn\'t find %s value' % cls.union_type_field)
+
+            data += instance.encode(instance)
+            return data
+
+        for field_ in fields(cls):
+            value = getattr(instance, field_.name)
+            if "format" in field_.metadata:
+                data += field_.metadata["format"].encode(value)
+            elif issubclass(field_.type, StructType):
+                if not isinstance(value, field_.type):
+                    raise ValueError('expected value of type %r for %s.%s, got %r' %
+                                     (field_.type, cls.__name__, field_.name, value))
+                data += value.encode(value)
+            else:
+                raise TypeError('field %s.%s has no format and is no StructType' %
+                                (cls.__class__.__name__, field_.name))
+        return data
+
+    @classmethod
+    def decode(cls, data: bytes) -> Self:
+        values = {}
+        for field_ in fields(cls):
+            if "format" in field_.metadata:
+                data = field_.metadata["format"].decode(data)
+            elif issubclass(field_.type, StructType):
+                data = field_.type.decode(data)
+            else:
+                raise TypeError('field %s.%s has no format and is no StructType' %
+                                (cls.__name__, field_.name))
+            values[field_.name] = field_.metadata["format"].decode(data)
+
+        if cls.union_type_field:
+            try:
+                type_value = values[cls.union_type_field]
+            except KeyError:
+                raise TypeError('union_type_field %s.%s is missing' %
+                                (cls.__name__, cls.union_type_field))
+            try:
+                klass = cls._union_options[type_value]
+            except KeyError:
+                raise TypeError('union_type_field %s.%s value %r no known' %
+                                (cls.__name__, cls.union_type_field, type_value))
+            return klass.decode(data)
+        return cls(**values)
+
+    @classmethod
+    def tojson(cls, instance) -> dict:
+        result = {}
+
+        if cls.union_type_field and type(instance) is not cls:
+            if not isinstance(instance, cls):
+                raise ValueError('expected value of type %r, got %r' % (cls, instance))
+
+            for field_ in fields(instance):
+                if field_.name is cls.union_type_field:
+                    result[field_.name] = field_.metadata["format"].encode(getattr(instance, field_.name))
+                    break
+            else:
+                raise TypeError('couldn\'t find %s value' % cls.union_type_field)
+
+            result.update(instance.tojson(instance))
+            return result
+
+        for field_ in fields(cls):
+            value = getattr(instance, field_.name)
+            if "format" in field_.metadata:
+                result[field_.name] = field_.metadata["format"].tojson(value)
+            elif issubclass(field_.type, StructType):
+                if not isinstance(value, field_.type):
+                    raise ValueError('expected value of type %r for %s.%s, got %r' %
+                                     (field_.type, cls.__name__, field_.name, value))
+                result[field_.name] = value.tojson(value)
+            else:
+                raise TypeError('field %s.%s has no format and is no StructType' %
+                                (cls.__class__.__name__, field_.name))
+        return result
+
+    @classmethod
+    def fromjson(cls, data):
+        data = data.copy()
+
+        # todo: upgrade_json
+
+        kwargs = {}
+        for field_ in fields(cls):
+            if "format" in field_.metadata:
+                data = field_.metadata["format"].decode(data)
+            elif issubclass(field_.type, StructType):
+                data = field_.type.decode(data)
+            else:
+                raise TypeError('field %s.%s has no format and is no StructType' %
+                                (cls.__name__, field_.name))
+            kwargs[field_.name], data = field_.metadata["format"].decode(data)
+
+        if cls.union_type_field:
+            try:
+                type_value = kwargs[cls.union_type_field]
+            except KeyError:
+                raise TypeError('union_type_field %s.%s is missing' %
+                                (cls.__name__, cls.union_type_field))
+            try:
+                klass = cls._union_options[type_value]
+            except KeyError:
+                raise TypeError('union_type_field %s.%s value %r no known' %
+                                (cls.__name__, cls.union_type_field, type_value))
+            return klass.fromjson(data)
+
+        return cls(**kwargs)
+
+    @classmethod
+    def get_c_struct_items(cls, ignore_fields=None, no_empty=False, top_level=False, union_only=False, in_union=False):
+        ignore_fields = set() if not ignore_fields else set(ignore_fields)
+
+        items = []
+
+        for field_ in fields(cls):
+            if field_.name in ignore_fields:
+                continue
+            if in_union and field_.metadata["defining_class"] != cls:
+                continue
+
+            name = field_.metadata.get("c_name", field_.name)
+            if "format" in field_.metadata:
+                if not field_.metadata.get("union_discriminator") or field_.metadata.get("defining_class") == cls:
+                    items.append((
+                        field_.metadata["format"].get_c_code(name),
+                        field_.metadata.get("doc", None),
+                    )),
+            elif issubclass(field_.type, StructType):
+                if field_.metadata.get("c_embed"):
+                    embedded_items = field_.type.get_c_struct_items(ignore_fields, no_empty, top_level, union_only)
+                    items.extend(embedded_items)
+                else:
+                    items.append((
+                        field_.type.get_c_code(name, typedef=False),
+                        field_.metadata.get("doc", None),
+                    ))
+            else:
+                raise TypeError('field %s.%s has no format and is no StructType' %
+                                (cls.__name__, field_.name))
+
+        if cls.union_type_field:
+            if not union_only:
+                union_code = cls.get_c_union_code(ignore_fields)
+                items.append(("union __packed %s;" % union_code, ""))
+
+        return items
+
+    @classmethod
+    def get_c_union_size(cls):
+        return max(
+            (option.get_min_size(no_inherited_fields=True) for option in
+             cls._union_options[cls.union_type_field].values()),
+            default=0,
+        )
+
+    @classmethod
+    def get_c_union_code(cls, ignore_fields=None):
+        union_items = []
+        for key, option in cls._union_options[cls.union_type_field].items():
+            base_name = normalize_name(getattr(key, 'name', option.__name__))
+            union_items.append(
+                option.get_c_code(base_name, ignore_fields=ignore_fields, typedef=False, in_union=True)
+            )
+        size = cls.get_c_union_size()
+        union_items.append(
+            "uint8_t bytes[%0d]; " % size
+        )
+        return "{\n" + indent_c("\n".join(union_items)) + "\n}"
+
+    @classmethod
+    def get_c_parts(cls, ignore_fields=None, no_empty=False, top_level=False, union_only=False, in_union=False):
+        ignore_fields = set() if not ignore_fields else set(ignore_fields)
+
+        if union_only:
+            if cls.union_type_field:
+                union_code = cls.get_c_union_code(ignore_fields)
+                return "typedef union __packed %s" % union_code, ""
+            else:
+                return "", ""
+
+        pre = ""
+
+        items = cls.get_c_struct_items(ignore_fields=ignore_fields,
+                                       no_empty=no_empty,
+                                       top_level=top_level,
+                                       union_only=union_only,
+                                       in_union=in_union)
+
+        if no_empty and not items:
+            return "", ""
+
+        # todo: struct comment
+        if top_level:
+            comment = cls.__doc__.strip()
+            if comment:
+                pre += "/** %s */\n" % comment
+            pre += "typedef struct __packed "
+        else:
+            pre += "struct __packed "
+
+        pre += "{\n%(elements)s\n}" % {
+            "elements": indent_c(
+                "\n".join(
+                    code + ("" if not comment else (" /** %s */" % comment))
+                    for code, comment in items
+                )
+            ),
+        }
+        return pre, ""
+
+    @classmethod
+    def get_c_code(cls, name=None, ignore_fields=None, no_empty=False, typedef=True, union_only=False,
+                   in_union=False) -> str:
+        pre, post = cls.get_c_parts(ignore_fields=ignore_fields,
+                                    no_empty=no_empty,
+                                    top_level=typedef,
+                                    union_only=union_only,
+                                    in_union=in_union)
+        if no_empty and not pre and not post:
+            return ""
+        return "%s %s%s;" % (pre, name, post)
+
+    @classmethod
+    def get_variable_name(cls, base_name):
+        return base_name
+
+    @classmethod
+    def get_struct_name(cls, base_name):
+        return "%s_t" % base_name
+
+    @classmethod
+    def get_min_size(cls, no_inherited_fields=False) -> int:
+        if cls.union_type_field:
+            own_size = sum([f.metadata.get("format", f.type).get_min_size() for f in fields(cls)])
+            union_size = max(
+                [0] + [option.get_min_size(True) for option in cls._union_options[cls.union_type_field].values()])
+            return own_size + union_size
+        if no_inherited_fields:
+            relevant_fields = [f for f in fields(cls) if f.metadata["defining_class"] == cls]
+        else:
+            relevant_fields = [f for f in fields(cls) if not f.metadata.get("union_discriminator")]
+        return sum((f.metadata.get("format", f.type).get_min_size() for f in relevant_fields), start=0)
+
+
+def normalize_name(name):
+    if '_' in name:
+        return name.lower()
+    return re.sub(
+        r"([a-z])([A-Z])",
+        r"\1_\2",
+        name
+    ).lower()
diff --git a/src/c3nav/mesh/dataformats.py b/src/c3nav/mesh/dataformats.py
index f4c47ee0..90de1d37 100644
--- a/src/c3nav/mesh/dataformats.py
+++ b/src/c3nav/mesh/dataformats.py
@@ -462,26 +462,27 @@ class MacAddressesListFormat(VarArrayFormat):
         super().__init__(child_type=MacAddressFormat())
 
 
-""" stuff """
 
 @unique
 class LedType(IntEnum):
     SERIAL = 1
     MULTIPIN = 2
 
+
 @dataclass
 class LedConfig(StructType, union_type_field="led_type"):
-    led_type: LedType = field(init=False, repr=False, metadata={"format": SimpleFormat('B')})
+    led_type: LedType = field(metadata={"format": SimpleFormat('B')})
+    leds_are_cool: int = field(metadata={"format": SimpleFormat('B')})
 
 
 @dataclass
-class SerialLedConfig(LedConfig, StructType, led_type=LedType.SERIAL):
+class SerialLedConfig(LedConfig, led_type=LedType.SERIAL):
     gpio: int = field(metadata={"format": SimpleFormat('B')})
     rmt: int = field(metadata={"format": SimpleFormat('B')})
 
 
 @dataclass
-class MultipinLedConfig(LedConfig, StructType, led_type=LedType.MULTIPIN):
+class MultipinLedConfig(LedConfig, led_type=LedType.MULTIPIN):
     gpio_red: int = field(metadata={"format": SimpleFormat('B')})
     gpio_green: int = field(metadata={"format": SimpleFormat('B')})
     gpio_blue: int = field(metadata={"format": SimpleFormat('B')})
@@ -491,3 +492,17 @@ class MultipinLedConfig(LedConfig, StructType, led_type=LedType.MULTIPIN):
 class RangeItemType(StructType):
     address: str = field(metadata={"format": MacAddressFormat()})
     distance: int = field(metadata={"format": SimpleFormat('H')})
+
+
+@dataclass
+class FirmwareAppDescription(StructType, no_c_type=True):
+    magic_word: int = field(metadata={"format": SimpleFormat('I')}, repr=False)
+    secure_version: int = field(metadata={"format": SimpleFormat('I')})
+    reserv1: list[int] = field(metadata={"format": SimpleFormat('2I')}, repr=False)
+    version: str = field(metadata={"format": FixedStrFormat(32)})
+    project_name: str = field(metadata={"format": FixedStrFormat(32)})
+    compile_time: str = field(metadata={"format": FixedStrFormat(16)})
+    compile_date: str = field(metadata={"format": FixedStrFormat(16)})
+    idf_version: str = field(metadata={"format": FixedStrFormat(32)})
+    app_elf_sha256: str = field(metadata={"format": FixedHexFormat(32)})
+    reserv2: list[int] = field(metadata={"format": SimpleFormat('20I')}, repr=False)
\ No newline at end of file
diff --git a/src/c3nav/mesh/management/commands/mesh_msg_c.py b/src/c3nav/mesh/management/commands/mesh_msg_c.py
index c8175edd..28ab7d68 100644
--- a/src/c3nav/mesh/management/commands/mesh_msg_c.py
+++ b/src/c3nav/mesh/management/commands/mesh_msg_c.py
@@ -2,7 +2,8 @@ from dataclasses import fields
 
 from django.core.management.base import BaseCommand
 
-from c3nav.mesh.dataformats import normalize_name, LedConfig
+from c3nav.mesh.dataformats import LedConfig
+from c3nav.mesh.baseformats import normalize_name
 from c3nav.mesh.messages import MeshMessage, MeshMessageType
 from c3nav.mesh.utils import indent_c
 
@@ -17,10 +18,11 @@ class Command(BaseCommand):
         name = name.replace('firmware', 'fw')
         return name
 
-    def handle(self, *args, **options):
+    def handle(self,  *args, **options):
         done_struct_names = set()
         nodata = set()
         struct_lines = {}
+        struct_sizes = []
 
         ignore_names = set(field_.name for field_ in fields(MeshMessage))
         for msg_id, msg_type in MeshMessage.get_types().items():
@@ -35,13 +37,13 @@ class Command(BaseCommand):
             )))
             name = "mesh_msg_%s_t" % base_name
 
-            if msg_id == MeshMessageType.CONFIG_LED:
-                msg_type = LedConfig
-
             code = msg_type.get_c_code(name, ignore_fields=ignore_names, no_empty=True)
             if code:
+                size = msg_type.get_min_size(no_inherited_fields=True)
                 struct_lines[base_name] = "%s %s;" % (name, base_name.replace('_announce', ''))
+                struct_sizes.append(size)
                 print(code)
+                print("static_assert(sizeof(%s) == %d, \"size of generated message structs is calculated wrong\");" % (name, size))
                 print()
             else:
                 nodata.add(msg_type)
@@ -50,8 +52,8 @@ class Command(BaseCommand):
         print("typedef union __packed {")
         for line in struct_lines.values():
             print(indent_c(line))
-        print("} mesh_msg_data_t;")
-        print()
+        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))
 
         max_msg_type = max(MeshMessage.get_types().keys())
         macro_data = []
diff --git a/src/c3nav/mesh/messages.py b/src/c3nav/mesh/messages.py
index f4987dff..fa394067 100644
--- a/src/c3nav/mesh/messages.py
+++ b/src/c3nav/mesh/messages.py
@@ -8,9 +8,10 @@ import channels
 from asgiref.sync import async_to_sync
 
 from c3nav.mesh.utils import get_mesh_comm_group, indent_c
-from c3nav.mesh.dataformats import (BoolFormat, FixedStrFormat, FixedHexFormat, LedConfig, LedConfig,
-                                    MacAddressesListFormat, MacAddressFormat, SimpleFormat, VarStrFormat, StructType,
-                                    VarArrayFormat, RangeItemType)
+from c3nav.mesh.dataformats import (LedConfig, LedConfig,
+                                    MacAddressesListFormat, MacAddressFormat, RangeItemType, FirmwareAppDescription)
+from c3nav.mesh.baseformats import SimpleFormat, BoolFormat, FixedStrFormat, FixedHexFormat, VarArrayFormat, \
+    VarStrFormat, StructType
 
 MESH_ROOT_ADDRESS = '00:00:00:00:00:00'
 MESH_PARENT_ADDRESS = '00:00:00:ff:ff:ff'
@@ -31,6 +32,7 @@ class MeshMessageType(IntEnum):
     MESH_ROUTE_REQUEST = 0x07
     MESH_ROUTE_RESPONSE = 0x08
     MESH_ROUTE_TRACE = 0x09
+    MESH_ROUTING_FAILED = 0x0a
 
     CONFIG_DUMP = 0x10
     CONFIG_FIRMWARE = 0x11
@@ -83,12 +85,6 @@ class MeshMessage(StructType, union_type_field="msg_id"):
     def get_additional_c_fields(self):
         return ()
 
-    @classmethod
-    def get_var_num(cls):
-        return 0
-        # todo: fix
-        return sum((getattr(field.metadata["format"], "var_num", 0) for field in fields(cls)), start=0)
-
     @classmethod
     def get_variable_name(cls, base_name):
         return cls.c_struct_name or base_name
@@ -201,6 +197,12 @@ class MeshRouteTraceMessage(MeshMessage, msg_id=MeshMessageType.MESH_ROUTE_TRACE
     })
 
 
+@dataclass
+class MeshRoutingFailedMessage(MeshMessage, msg_id=MeshMessageType.MESH_ROUTING_FAILED):
+    """ TODO description"""
+    address: str = field(metadata={"format": MacAddressFormat()})
+
+
 @dataclass
 class ConfigDumpMessage(MeshMessage, msg_id=MeshMessageType.CONFIG_DUMP):
     """ request for the node to dump its config """
@@ -216,16 +218,7 @@ class ConfigFirmwareMessage(MeshMessage, msg_id=MeshMessageType.CONFIG_FIRMWARE)
     })
     revision_major: int = field(metadata={"format": SimpleFormat('B')})
     revision_minor: int = field(metadata={"format": SimpleFormat('B')})
-    magic_word: int = field(metadata={"format": SimpleFormat('I')}, repr=False)
-    secure_version: int = field(metadata={"format": SimpleFormat('I')})
-    reserv1: list[int] = field(metadata={"format": SimpleFormat('2I')}, repr=False)
-    version: str = field(metadata={"format": FixedStrFormat(32)})
-    project_name: str = field(metadata={"format": FixedStrFormat(32)})
-    compile_time: str = field(metadata={"format": FixedStrFormat(16)})
-    compile_date: str = field(metadata={"format": FixedStrFormat(16)})
-    idf_version: str = field(metadata={"format": FixedStrFormat(32)})
-    app_elf_sha256: str = field(metadata={"format": FixedHexFormat(32)})
-    reserv2: list[int] = field(metadata={"format": SimpleFormat('20I')}, repr=False)
+    app_desc: FirmwareAppDescription = field(metadata={'json_embed': True})
 
     @classmethod
     def upgrade_json(cls, data):
@@ -259,7 +252,7 @@ class ConfigPositionMessage(MeshMessage, msg_id=MeshMessageType.CONFIG_POSITION)
 @dataclass
 class ConfigLedMessage(MeshMessage, msg_id=MeshMessageType.CONFIG_LED):
     """ set/respond led config """
-    led_config: LedConfig = field(metadata={})
+    led_config: LedConfig = field(metadata={"c_embed": True})
 
 
 @dataclass