diff --git a/components/esp_timer/include/esp_timer.h b/components/esp_timer/include/esp_timer.h
index 9e76c0c4c2..762bb0b77d 100644
--- a/components/esp_timer/include/esp_timer.h
+++ b/components/esp_timer/include/esp_timer.h
@@ -1,16 +1,8 @@
-// Copyright 2017 Espressif Systems (Shanghai) PTE LTD
-//
-// Licensed under the Apache License, Version 2.0 (the "License");
-// you may not use this file except in compliance with the License.
-// You may obtain a copy of the License at
-//
-//     http://www.apache.org/licenses/LICENSE-2.0
-//
-// Unless required by applicable law or agreed to in writing, software
-// distributed under the License is distributed on an "AS IS" BASIS,
-// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-// See the License for the specific language governing permissions and
-// limitations under the License.
+/*
+ * SPDX-FileCopyrightText: 2017-2021 Espressif Systems (Shanghai) CO LTD
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ */
 
 #pragma once
 
diff --git a/components/esp_timer/private_include/esp_timer_impl.h b/components/esp_timer/private_include/esp_timer_impl.h
index bcecc21ef0..f2cd26fe86 100644
--- a/components/esp_timer/private_include/esp_timer_impl.h
+++ b/components/esp_timer/private_include/esp_timer_impl.h
@@ -1,16 +1,8 @@
-// Copyright 2017 Espressif Systems (Shanghai) PTE LTD
-//
-// Licensed under the Apache License, Version 2.0 (the "License");
-// you may not use this file except in compliance with the License.
-// You may obtain a copy of the License at
-//
-//     http://www.apache.org/licenses/LICENSE-2.0
-//
-// Unless required by applicable law or agreed to in writing, software
-// distributed under the License is distributed on an "AS IS" BASIS,
-// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-// See the License for the specific language governing permissions and
-// limitations under the License.
+/*
+ * SPDX-FileCopyrightText: 2017-2021 Espressif Systems (Shanghai) CO LTD
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ */
 
 #pragma once
 
diff --git a/components/esp_timer/src/esp_timer.c b/components/esp_timer/src/esp_timer.c
index 873739f87b..e83a3c4398 100644
--- a/components/esp_timer/src/esp_timer.c
+++ b/components/esp_timer/src/esp_timer.c
@@ -1,16 +1,8 @@
-// Copyright 2017 Espressif Systems (Shanghai) PTE LTD
-//
-// Licensed under the Apache License, Version 2.0 (the "License");
-// you may not use this file except in compliance with the License.
-// You may obtain a copy of the License at
-//
-//     http://www.apache.org/licenses/LICENSE-2.0
-//
-// Unless required by applicable law or agreed to in writing, software
-// distributed under the License is distributed on an "AS IS" BASIS,
-// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-// See the License for the specific language governing permissions and
-// limitations under the License.
+/*
+ * SPDX-FileCopyrightText: 2017-2021 Espressif Systems (Shanghai) CO LTD
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ */
 
 #include <sys/param.h>
 #include <string.h>
@@ -366,7 +358,11 @@ static IRAM_ATTR inline bool is_initialized(void)
 
 esp_err_t esp_timer_early_init(void)
 {
-    return esp_timer_impl_early_init();
+    esp_timer_impl_early_init();
+#if CONFIG_ESP_TIME_FUNCS_USE_ESP_TIMER
+    esp_timer_impl_init_system_time();
+#endif
+    return ESP_OK;
 }
 
 esp_err_t esp_timer_init(void)
@@ -388,10 +384,6 @@ esp_err_t esp_timer_init(void)
         goto out;
     }
 
-#if CONFIG_ESP_TIME_FUNCS_USE_ESP_TIMER
-    esp_timer_impl_init_system_time();
-#endif
-
     return ESP_OK;
 
 out:
diff --git a/components/esp_timer/src/esp_timer_impl_lac.c b/components/esp_timer/src/esp_timer_impl_lac.c
index 819c79dc50..8b48d04258 100644
--- a/components/esp_timer/src/esp_timer_impl_lac.c
+++ b/components/esp_timer/src/esp_timer_impl_lac.c
@@ -1,16 +1,8 @@
-// Copyright 2020 Espressif Systems (Shanghai) PTE LTD
-//
-// Licensed under the Apache License, Version 2.0 (the "License");
-// you may not use this file except in compliance with the License.
-// You may obtain a copy of the License at
-//
-//     http://www.apache.org/licenses/LICENSE-2.0
-//
-// Unless required by applicable law or agreed to in writing, software
-// distributed under the License is distributed on an "AS IS" BASIS,
-// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-// See the License for the specific language governing permissions and
-// limitations under the License.
+/*
+ * SPDX-FileCopyrightText: 2017-2021 Espressif Systems (Shanghai) CO LTD
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ */
 
 #include "sys/param.h"
 #include "esp_timer_impl.h"
diff --git a/components/esp_timer/src/esp_timer_impl_systimer.c b/components/esp_timer/src/esp_timer_impl_systimer.c
index 39149d85ac..21f60c3b46 100644
--- a/components/esp_timer/src/esp_timer_impl_systimer.c
+++ b/components/esp_timer/src/esp_timer_impl_systimer.c
@@ -1,16 +1,8 @@
-// Copyright 2017-2020 Espressif Systems (Shanghai) PTE LTD
-//
-// Licensed under the Apache License, Version 2.0 (the "License");
-// you may not use this file except in compliance with the License.
-// You may obtain a copy of the License at
-//
-//     http://www.apache.org/licenses/LICENSE-2.0
-//
-// Unless required by applicable law or agreed to in writing, software
-// distributed under the License is distributed on an "AS IS" BASIS,
-// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-// See the License for the specific language governing permissions and
-// limitations under the License.
+/*
+ * SPDX-FileCopyrightText: 2017-2021 Espressif Systems (Shanghai) CO LTD
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ */
 
 #include "esp_timer_impl.h"
 #include "esp_err.h"