diff --git a/components/esp_timer/include/esp_timer.h b/components/esp_timer/include/esp_timer.h
index 02f9379736..eb4c6d707a 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 888461f9fa..d59a13eb13 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 375cad6c4d..fbabcfda4a 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>
@@ -430,7 +422,11 @@ 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)
@@ -452,10 +448,6 @@ 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 13338f0874..a9c93ef0fe 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 833e845460..b279ab213d 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 "sys/param.h"
 #include "esp_timer_impl.h"
diff --git a/tools/ci/check_copyright_ignore.txt b/tools/ci/check_copyright_ignore.txt
index 6d810a80e1..2178ab28a3 100644
--- a/tools/ci/check_copyright_ignore.txt
+++ b/tools/ci/check_copyright_ignore.txt
@@ -1159,12 +1159,7 @@ components/esp_system/test_eh_frame_parser/linker.ld
 components/esp_system/test_eh_frame_parser/main.c
 components/esp_system/ubsan.c
 components/esp_timer/include/esp_private/esp_timer_private.h
-components/esp_timer/include/esp_timer.h
-components/esp_timer/private_include/esp_timer_impl.h
-components/esp_timer/src/esp_timer.c
 components/esp_timer/src/esp_timer_impl_frc_legacy.c
-components/esp_timer/src/esp_timer_impl_lac.c
-components/esp_timer/src/esp_timer_impl_systimer.c
 components/esp_timer/src/ets_timer_legacy.c
 components/esp_timer/src/system_time.c
 components/esp_timer/test/test_esp_timer.c