diff --git a/telethon/_client/telegrambaseclient.py b/telethon/_client/telegrambaseclient.py
index 1050c2a5..1add1abb 100644
--- a/telethon/_client/telegrambaseclient.py
+++ b/telethon/_client/telegrambaseclient.py
@@ -319,6 +319,9 @@ async def connect(self: 'TelegramClient') -> None:
     # TODO Get state from channels too
     self._state_cache = statecache.StateCache(state, self._log)
 
+    # Use known key, if any
+    self._sender.auth_key.key = dc.auth
+
     if not await self._sender.connect(self._connection(
         str(ipaddress.ip_address(dc.ipv6 or dc.ipv4)),
         dc.port,
@@ -330,8 +333,8 @@ async def connect(self: 'TelegramClient') -> None:
         # We don't want to init or modify anything if we were already connected
         return
 
-    if self._sender.auth_key.key != dc.key:
-        dc.key = self._sender.auth_key.key
+    if self._sender.auth_key.key != dc.auth:
+        dc.auth = self._sender.auth_key.key
         await self.session.insert_dc(dc)
         await self.session.save()
 
diff --git a/telethon/_client/users.py b/telethon/_client/users.py
index 394baee9..18a6f0f4 100644
--- a/telethon/_client/users.py
+++ b/telethon/_client/users.py
@@ -271,19 +271,18 @@ async def get_input_entity(
 
     # No InputPeer, cached peer, or known string. Fetch from session cache
     try:
-        peer = utils.get_peer(peer)
-        if isinstance(peer, _tl.PeerUser):
-            entity = await self.session.get_entity(Entity.USER, peer.user_id)
-            if entity:
-                return _tl.InputPeerUser(entity.id, entity.access_hash)
-        elif isinstance(peer, _tl.PeerChat):
-            return _tl.InputPeerChat(peer.chat_id)
-        elif isinstance(peer, _tl.PeerChannel):
-            entity = await self.session.get_entity(Entity.CHANNEL, peer.user_id)
-            if entity:
-                return _tl.InputPeerChannel(entity.id, entity.access_hash)
-    except ValueError:
+        peer_id = utils.get_peer_id(peer)
+    except TypeError:
         pass
+    else:
+        entity = await self.session.get_entity(None, peer_id)
+        if entity:
+            if entity.ty in (Entity.USER, Entity.BOT):
+                return _tl.InputPeerUser(entity.id, entity.access_hash)
+            elif entity.ty in (Entity.GROUP):
+                return _tl.InputPeerChat(peer.chat_id)
+            elif entity.ty in (Entity.CHANNEL, Entity.MEGAGROUP, Entity.GIGAGROUP):
+                return _tl.InputPeerChannel(entity.id, entity.access_hash)
 
     # Only network left to try
     if isinstance(peer, str):
diff --git a/telethon/sessions/abstract.py b/telethon/sessions/abstract.py
index 4cdc9131..2b28ae76 100644
--- a/telethon/sessions/abstract.py
+++ b/telethon/sessions/abstract.py
@@ -59,7 +59,7 @@ class Session(ABC):
         raise NotImplementedError
 
     @abstractmethod
-    async def get_entity(self, ty: int, id: int) -> Optional[Entity]:
+    async def get_entity(self, ty: Optional[int], id: int) -> Optional[Entity]:
         """
         Get the `Entity` with matching ``ty`` and ``id``.
 
@@ -75,6 +75,8 @@ class Session(ABC):
         the corresponding ``access_hash`` should still be returned.
 
         You may use `types.canonical_entity_type` to find out the canonical type.
+
+        A ``ty`` with the value of ``None`` should be treated as "any entity with matching ID".
         """
         raise NotImplementedError
 
diff --git a/telethon/sessions/memory.py b/telethon/sessions/memory.py
index 67602ec9..1c86aff7 100644
--- a/telethon/sessions/memory.py
+++ b/telethon/sessions/memory.py
@@ -36,7 +36,7 @@ class MemorySession(Session):
     async def insert_entities(self, entities: List[Entity]):
         self.entities.update((e.id, (e.ty, e.access_hash)) for e in entities)
 
-    async def get_entity(self, ty: int, id: int) -> Optional[Entity]:
+    async def get_entity(self, ty: Optional[int], id: int) -> Optional[Entity]:
         try:
             ty, access_hash = self.entities[id]
             return Entity(ty, id, access_hash)
diff --git a/telethon/sessions/sqlite.py b/telethon/sessions/sqlite.py
index 5cd288aa..5bfc0433 100644
--- a/telethon/sessions/sqlite.py
+++ b/telethon/sessions/sqlite.py
@@ -55,13 +55,17 @@ class SQLiteSession(Session):
                 self._upgrade_database(old=version)
                 c.execute("delete from version")
                 c.execute("insert into version values (?)", (CURRENT_VERSION,))
-                self.save()
+                self._conn.commit()
         else:
             # Tables don't exist, create new ones
+            self._create_table(c, 'version (version integer primary key)')
             self._mk_tables(c)
             c.execute("insert into version values (?)", (CURRENT_VERSION,))
-            c.close()
-            self.save()
+            self._conn.commit()
+
+        # Must have committed or else the version will not have been updated while new tables
+        # exist, leading to a half-upgraded state.
+        c.close()
 
     def _upgrade_database(self, old):
         c = self._cursor()
@@ -146,9 +150,6 @@ class SQLiteSession(Session):
     def _mk_tables(self, c):
         self._create_table(
             c,
-            '''version (
-                version integer primary key
-            )''',
             '''datacenter (
                 id integer primary key,
                 ip text not null,
@@ -243,7 +244,7 @@ class SQLiteSession(Session):
         finally:
             c.close()
 
-    async def get_entity(self, ty: int, id: int) -> Optional[Entity]:
+    async def get_entity(self, ty: Optional[int], id: int) -> Optional[Entity]:
         row = self._execute('select ty, id, access_hash from entity where id = ?', id)
         return Entity(*row) if row else None