diff --git a/DEVELOPING.md b/DEVELOPING.md
index 342e776d..b248bea0 100644
--- a/DEVELOPING.md
+++ b/DEVELOPING.md
@@ -1,5 +1,13 @@
+Code generation:
+
 ```sh
 pip install -e generator/
-python -m telethon_generator.codegen api.tl telethon/src/_impl/tl
-python -m telethon_generator.codegen mtproto.tl telethon/src/_impl/tl/mtproto
+python -m telethon_generator.codegen api.tl client/src/telethon/_impl/tl
+python -m telethon_generator.codegen mtproto.tl client/src/telethon/_impl/tl/mtproto
+```
+
+Formatting, type-checking and testing:
+
+```
+./check.sh
 ```
diff --git a/client/src/telethon/_impl/tl/core/reader.py b/client/src/telethon/_impl/tl/core/reader.py
index cd608a36..8d5f5338 100644
--- a/client/src/telethon/_impl/tl/core/reader.py
+++ b/client/src/telethon/_impl/tl/core/reader.py
@@ -1,5 +1,5 @@
 import struct
-from typing import TYPE_CHECKING, Any, Type, TypeVar
+from typing import TYPE_CHECKING, Any, Optional, Type, TypeVar
 
 if TYPE_CHECKING:
     from .serializable import Serializable
@@ -8,6 +8,26 @@ if TYPE_CHECKING:
 T = TypeVar("T", bound="Serializable")
 
 
+def _bootstrap_get_ty(constructor_id: int) -> Optional[Type["Serializable"]]:
+    # Lazy import because generate code depends on the Reader.
+    # After the first call, the class method is replaced with direct access.
+    if Reader._get_ty is _bootstrap_get_ty:
+        from ..layer import TYPE_MAPPING as API_TYPES
+        from ..mtproto.layer import TYPE_MAPPING as MTPROTO_TYPES
+
+        if API_TYPES.keys() & MTPROTO_TYPES.keys():
+            raise RuntimeError(
+                "generated api and mtproto schemas cannot have colliding constructor identifiers"
+            )
+        ALL_TYPES = API_TYPES | MTPROTO_TYPES
+
+        # Signatures don't fully match, but this is a private method
+        # and all previous uses are compatible with `dict.get`.
+        Reader._get_ty = ALL_TYPES.get  # type: ignore [assignment]
+
+    return Reader._get_ty(constructor_id)
+
+
 class Reader:
     __slots__ = ("_buffer", "_pos", "_view")
 
@@ -44,11 +64,7 @@ class Reader:
 
         return data
 
-    @staticmethod
-    def _get_ty(_: int) -> Type["Serializable"]:
-        # Implementation replaced during import to prevent cycles,
-        # without the performance hit of having the import inside.
-        raise NotImplementedError
+    _get_ty = staticmethod(_bootstrap_get_ty)
 
     def read_serializable(self, cls: Type[T]) -> T:
         # Calls to this method likely need to ignore "type-abstract".
diff --git a/client/src/telethon/_impl/tl/core/serializable.py b/client/src/telethon/_impl/tl/core/serializable.py
index e5072559..622c0a32 100644
--- a/client/src/telethon/_impl/tl/core/serializable.py
+++ b/client/src/telethon/_impl/tl/core/serializable.py
@@ -38,6 +38,13 @@ class Serializable(abc.ABC):
         attrs = ", ".join(repr(getattr(self, attr)) for attr in self.__slots__)
         return f"{self.__class__.__name__}({attrs})"
 
+    def __eq__(self, other: object) -> bool:
+        if not isinstance(other, self.__class__):
+            return NotImplemented
+        return all(
+            getattr(self, attr) == getattr(other, attr) for attr in self.__slots__
+        )
+
 
 def serialize_bytes_to(buffer: bytearray, data: bytes) -> None:
     length = len(data)
diff --git a/client/src/telethon/_impl/tl/mtproto/__init__.py b/client/src/telethon/_impl/tl/mtproto/__init__.py
new file mode 100644
index 00000000..1d0af0b3
--- /dev/null
+++ b/client/src/telethon/_impl/tl/mtproto/__init__.py
@@ -0,0 +1,4 @@
+from . import abcs, functions, types
+from .layer import TYPE_MAPPING
+
+__all__ = ["abcs", "functions", "types", "TYPE_MAPPING"]
diff --git a/client/tests/reader_test.py b/client/tests/reader_test.py
index 52636f81..04946f45 100644
--- a/client/tests/reader_test.py
+++ b/client/tests/reader_test.py
@@ -1,5 +1,10 @@
+import struct
+
 from pytest import mark
 from telethon._impl.tl.core import Reader
+from telethon._impl.tl.core.serializable import Serializable
+from telethon._impl.tl.mtproto.types import BadServerSalt
+from telethon._impl.tl.types import GeoPoint
 
 
 @mark.parametrize(
@@ -24,3 +29,21 @@ sentence made it past!",
 def test_string(string: str, prefix: bytes, suffix: bytes) -> None:
     data = prefix + string.encode("ascii") + suffix
     assert str(Reader(data).read_bytes(), "ascii") == string
+
+
+@mark.parametrize(
+    "obj",
+    [
+        GeoPoint(long=12.34, lat=56.78, access_hash=123123, accuracy_radius=100),
+        BadServerSalt(
+            bad_msg_id=1234,
+            bad_msg_seqno=5678,
+            error_code=9876,
+            new_server_salt=5432,
+        ),
+    ],
+)
+def test_generated_object(obj: Serializable) -> None:
+    assert bytes(obj)[:4] == struct.pack("<I", obj.constructor_id())
+    assert type(obj)._read_from(Reader(bytes(obj)[4:])) == obj
+    assert Reader(bytes(obj)).read_serializable(type(obj)) == obj
diff --git a/generator/src/telethon_generator/_impl/codegen/generator.py b/generator/src/telethon_generator/_impl/codegen/generator.py
index 15617d73..e08e28f3 100644
--- a/generator/src/telethon_generator/_impl/codegen/generator.py
+++ b/generator/src/telethon_generator/_impl/codegen/generator.py
@@ -115,7 +115,7 @@ def generate(fs: FakeFs, tl: ParsedTl) -> None:
             params = "".join(
                 f", {p.name}: {param_type_fmt(p.ty)}" for p in property_params
             )
-            writer.write(f"  def __init__(_s{params}) -> None:")
+            writer.write(f"  def __init__(_s, *{params}) -> None:")
             for p in property_params:
                 writer.write(f"    _s.{p.name} = {p.name}")
 
@@ -183,7 +183,4 @@ def generate(fs: FakeFs, tl: ParsedTl) -> None:
     for name in sorted(generated_type_names):
         writer.write(f"  types.{name},")
     writer.write("))}")
-    writer.write(
-        "Reader._get_ty = TYPE_MAPPING.get  # type: ignore [method-assign, assignment]"
-    )
     writer.write(f"__all__ = ['LAYER', 'TYPE_MAPPING']")