diff --git a/daemon/core/api/grpc/server.py b/daemon/core/api/grpc/server.py
index 69822252..8796d604 100644
--- a/daemon/core/api/grpc/server.py
+++ b/daemon/core/api/grpc/server.py
@@ -1179,7 +1179,7 @@ class CoreGrpcServer(core_pb2_grpc.CoreApiServicer):
         logger.debug("open xml: %s", request)
         session = self.coreemu.create_session()
         temp = tempfile.NamedTemporaryFile(delete=False)
-        temp.write(request.data.encode("utf-8"))
+        temp.write(request.data.encode())
         temp.close()
         temp_path = Path(temp.name)
         file_path = Path(request.file)
diff --git a/daemon/core/emulator/distributed.py b/daemon/core/emulator/distributed.py
index 57e9d1ef..1c0d3c92 100644
--- a/daemon/core/emulator/distributed.py
+++ b/daemon/core/emulator/distributed.py
@@ -105,7 +105,7 @@ class DistributedServer:
         """
         with self.lock:
             temp = NamedTemporaryFile(delete=False)
-            temp.write(data.encode("utf-8"))
+            temp.write(data.encode())
             temp.close()
             self.conn.put(temp.name, str(dst_path))
             os.unlink(temp.name)
diff --git a/daemon/core/nodes/docker.py b/daemon/core/nodes/docker.py
index ba470167..053d1c5e 100644
--- a/daemon/core/nodes/docker.py
+++ b/daemon/core/nodes/docker.py
@@ -227,7 +227,7 @@ class DockerNode(CoreNode):
         """
         logger.debug("node(%s) create file(%s) mode(%o)", self.name, file_path, mode)
         temp = NamedTemporaryFile(delete=False)
-        temp.write(contents.encode("utf-8"))
+        temp.write(contents.encode())
         temp.close()
         temp_path = Path(temp.name)
         directory = file_path.parent
diff --git a/daemon/core/nodes/lxd.py b/daemon/core/nodes/lxd.py
index 497c228e..e4cba002 100644
--- a/daemon/core/nodes/lxd.py
+++ b/daemon/core/nodes/lxd.py
@@ -170,7 +170,7 @@ class LxcNode(CoreNode):
         """
         logger.debug("node(%s) create file(%s) mode(%o)", self.name, file_path, mode)
         temp = NamedTemporaryFile(delete=False)
-        temp.write(contents.encode("utf-8"))
+        temp.write(contents.encode())
         temp.close()
         temp_path = Path(temp.name)
         directory = file_path.parent
diff --git a/daemon/core/utils.py b/daemon/core/utils.py
index 5947c006..2cfd3605 100644
--- a/daemon/core/utils.py
+++ b/daemon/core/utils.py
@@ -87,7 +87,7 @@ def hashkey(value: Union[str, int]) -> int:
     """
     if isinstance(value, int):
         value = str(value)
-    value = value.encode("utf-8")
+    value = value.encode()
     return int(hashlib.sha256(value).hexdigest(), 16)
 
 
@@ -224,9 +224,9 @@ def cmd(
         p = Popen(args, stdout=output, stderr=output, env=env, cwd=cwd, shell=shell)
         if wait:
             stdout, stderr = p.communicate()
-            stdout = stdout.decode("utf-8").strip()
-            stderr = stderr.decode("utf-8").strip()
-            status = p.wait()
+            stdout = stdout.decode().strip()
+            stderr = stderr.decode().strip()
+            status = p.returncode
             if status != 0:
                 raise CoreCommandError(status, input_args, stdout, stderr)
             return stdout