diff --git a/.github/workflows/publish.yml b/.github/workflows/publish.yml
index 6d4e51f..d541818 100644
--- a/.github/workflows/publish.yml
+++ b/.github/workflows/publish.yml
@@ -1,3 +1,10 @@
+#
+# This file is part of the micropython-esp32-ulp project,
+# https://github.com/micropython/micropython-esp32-ulp
+#
+# SPDX-FileCopyrightText: 2018-2023, the micropython-esp32-ulp authors, see AUTHORS file.
+# SPDX-License-Identifier: MIT
+
 name: Publish Python Package
 
 on:
diff --git a/.github/workflows/run_tests.yaml b/.github/workflows/run_tests.yaml
index 40ef419..72f6917 100644
--- a/.github/workflows/run_tests.yaml
+++ b/.github/workflows/run_tests.yaml
@@ -1,3 +1,10 @@
+#
+# This file is part of the micropython-esp32-ulp project,
+# https://github.com/micropython/micropython-esp32-ulp
+#
+# SPDX-FileCopyrightText: 2018-2023, the micropython-esp32-ulp authors, see AUTHORS file.
+# SPDX-License-Identifier: MIT
+
 name: CI
 
 on: [push, pull_request]
diff --git a/LICENSE b/LICENSE
index d3c5838..7fa80dd 100644
--- a/LICENSE
+++ b/LICENSE
@@ -1,6 +1,6 @@
 The MIT License (MIT)
 
-Copyright 2018-2022 by the micropython-esp32-ulp authors, see AUTHORS file
+Copyright 2018-2023 by the micropython-esp32-ulp authors, see AUTHORS file
 
 Permission is hereby granted, free of charge, to any person obtaining a copy
 of this software and associated documentation files (the "Software"), to deal
diff --git a/demo.S b/demo.S
index e2feac5..0522924 100644
--- a/demo.S
+++ b/demo.S
@@ -1,3 +1,10 @@
+#
+# This file is part of the micropython-esp32-ulp project,
+# https://github.com/micropython/micropython-esp32-ulp
+#
+# SPDX-FileCopyrightText: 2018-2023, the micropython-esp32-ulp authors, see AUTHORS file.
+# SPDX-License-Identifier: MIT
+
 # comment-only line
 
             .text
diff --git a/demo.sh b/demo.sh
index 4694862..6dea9b6 100644
--- a/demo.sh
+++ b/demo.sh
@@ -1 +1,8 @@
+#
+# This file is part of the micropython-esp32-ulp project,
+# https://github.com/micropython/micropython-esp32-ulp
+#
+# SPDX-FileCopyrightText: 2018-2023, the micropython-esp32-ulp authors, see AUTHORS file.
+# SPDX-License-Identifier: MIT
+
 micropython -m esp32_ulp demo.S
diff --git a/esp32_ulp/__init__.py b/esp32_ulp/__init__.py
index 1536c16..634605d 100644
--- a/esp32_ulp/__init__.py
+++ b/esp32_ulp/__init__.py
@@ -1,3 +1,10 @@
+#
+# This file is part of the micropython-esp32-ulp project,
+# https://github.com/micropython/micropython-esp32-ulp
+#
+# SPDX-FileCopyrightText: 2018-2023, the micropython-esp32-ulp authors, see AUTHORS file.
+# SPDX-License-Identifier: MIT
+
 from .util import garbage_collect
 
 from .preprocess import preprocess
diff --git a/esp32_ulp/__main__.py b/esp32_ulp/__main__.py
index b28ea78..fc14320 100644
--- a/esp32_ulp/__main__.py
+++ b/esp32_ulp/__main__.py
@@ -1,3 +1,10 @@
+#
+# This file is part of the micropython-esp32-ulp project,
+# https://github.com/micropython/micropython-esp32-ulp
+#
+# SPDX-FileCopyrightText: 2018-2023, the micropython-esp32-ulp authors, see AUTHORS file.
+# SPDX-License-Identifier: MIT
+
 import sys
 from . import assemble_file
 
diff --git a/esp32_ulp/assemble.py b/esp32_ulp/assemble.py
index 7d1101f..8b79071 100644
--- a/esp32_ulp/assemble.py
+++ b/esp32_ulp/assemble.py
@@ -1,3 +1,10 @@
+#
+# This file is part of the micropython-esp32-ulp project,
+# https://github.com/micropython/micropython-esp32-ulp
+#
+# SPDX-FileCopyrightText: 2018-2023, the micropython-esp32-ulp authors, see AUTHORS file.
+# SPDX-License-Identifier: MIT
+
 """
 ESP32 ULP Co-Processor Assembler
 """
diff --git a/esp32_ulp/definesdb.py b/esp32_ulp/definesdb.py
index 4a05459..6c49256 100644
--- a/esp32_ulp/definesdb.py
+++ b/esp32_ulp/definesdb.py
@@ -1,3 +1,10 @@
+#
+# This file is part of the micropython-esp32-ulp project,
+# https://github.com/micropython/micropython-esp32-ulp
+#
+# SPDX-FileCopyrightText: 2018-2023, the micropython-esp32-ulp authors, see AUTHORS file.
+# SPDX-License-Identifier: MIT
+
 import os
 import btree
 from .util import file_exists
diff --git a/esp32_ulp/link.py b/esp32_ulp/link.py
index fd9332b..f0d81df 100644
--- a/esp32_ulp/link.py
+++ b/esp32_ulp/link.py
@@ -1,3 +1,10 @@
+#
+# This file is part of the micropython-esp32-ulp project,
+# https://github.com/micropython/micropython-esp32-ulp
+#
+# SPDX-FileCopyrightText: 2018-2023, the micropython-esp32-ulp authors, see AUTHORS file.
+# SPDX-License-Identifier: MIT
+
 from uctypes import struct, addressof, LITTLE_ENDIAN, UINT16, UINT32
 
 
diff --git a/esp32_ulp/nocomment.py b/esp32_ulp/nocomment.py
index 2ac9e8d..5845b34 100644
--- a/esp32_ulp/nocomment.py
+++ b/esp32_ulp/nocomment.py
@@ -1,3 +1,10 @@
+#
+# This file is part of the micropython-esp32-ulp project,
+# https://github.com/micropython/micropython-esp32-ulp
+#
+# SPDX-FileCopyrightText: 2018-2023, the micropython-esp32-ulp authors, see AUTHORS file.
+# SPDX-License-Identifier: MIT
+
 def remove_comments(s):
     """
     Remove comments of these styles:
diff --git a/esp32_ulp/opcodes.py b/esp32_ulp/opcodes.py
index 4efce0c..10fc3d1 100644
--- a/esp32_ulp/opcodes.py
+++ b/esp32_ulp/opcodes.py
@@ -1,3 +1,10 @@
+#
+# This file is part of the micropython-esp32-ulp project,
+# https://github.com/micropython/micropython-esp32-ulp
+#
+# SPDX-FileCopyrightText: 2018-2023, the micropython-esp32-ulp authors, see AUTHORS file.
+# SPDX-License-Identifier: MIT
+
 """
 ESP32 ULP Co-Processor Instructions
 """
diff --git a/esp32_ulp/opcodes_s2.py b/esp32_ulp/opcodes_s2.py
index 9c64642..91549af 100644
--- a/esp32_ulp/opcodes_s2.py
+++ b/esp32_ulp/opcodes_s2.py
@@ -1,3 +1,10 @@
+#
+# This file is part of the micropython-esp32-ulp project,
+# https://github.com/micropython/micropython-esp32-ulp
+#
+# SPDX-FileCopyrightText: 2018-2023, the micropython-esp32-ulp authors, see AUTHORS file.
+# SPDX-License-Identifier: MIT
+
 """
 ESP32 ULP Co-Processor Instructions
 """
diff --git a/esp32_ulp/parse_to_db.py b/esp32_ulp/parse_to_db.py
index ac61f98..7b76d9f 100644
--- a/esp32_ulp/parse_to_db.py
+++ b/esp32_ulp/parse_to_db.py
@@ -1,3 +1,10 @@
+#
+# This file is part of the micropython-esp32-ulp project,
+# https://github.com/micropython/micropython-esp32-ulp
+#
+# SPDX-FileCopyrightText: 2018-2023, the micropython-esp32-ulp authors, see AUTHORS file.
+# SPDX-License-Identifier: MIT
+
 import sys
 
 from .preprocess import Preprocessor
diff --git a/esp32_ulp/preprocess.py b/esp32_ulp/preprocess.py
index 03a9317..4b08749 100644
--- a/esp32_ulp/preprocess.py
+++ b/esp32_ulp/preprocess.py
@@ -1,3 +1,10 @@
+#
+# This file is part of the micropython-esp32-ulp project,
+# https://github.com/micropython/micropython-esp32-ulp
+#
+# SPDX-FileCopyrightText: 2018-2023, the micropython-esp32-ulp authors, see AUTHORS file.
+# SPDX-License-Identifier: MIT
+
 from . import nocomment
 from .util import split_tokens
 from .definesdb import DefinesDB
diff --git a/esp32_ulp/soc.py b/esp32_ulp/soc.py
index 1a8845c..a0af189 100644
--- a/esp32_ulp/soc.py
+++ b/esp32_ulp/soc.py
@@ -1,3 +1,10 @@
+#
+# This file is part of the micropython-esp32-ulp project,
+# https://github.com/micropython/micropython-esp32-ulp
+#
+# SPDX-FileCopyrightText: 2018-2023, the micropython-esp32-ulp authors, see AUTHORS file.
+# SPDX-License-Identifier: MIT
+
 """
 Address / Register definitions for the ESP32 SoC
 """
diff --git a/esp32_ulp/soc_s2.py b/esp32_ulp/soc_s2.py
index 1e35295..bcaca53 100644
--- a/esp32_ulp/soc_s2.py
+++ b/esp32_ulp/soc_s2.py
@@ -1,3 +1,10 @@
+#
+# This file is part of the micropython-esp32-ulp project,
+# https://github.com/micropython/micropython-esp32-ulp
+#
+# SPDX-FileCopyrightText: 2018-2023, the micropython-esp32-ulp authors, see AUTHORS file.
+# SPDX-License-Identifier: MIT
+
 """
 Address / Register definitions for the ESP32-S2 SoC
 """
diff --git a/esp32_ulp/soc_s3.py b/esp32_ulp/soc_s3.py
index 821b02c..d1d95fd 100644
--- a/esp32_ulp/soc_s3.py
+++ b/esp32_ulp/soc_s3.py
@@ -1,3 +1,10 @@
+#
+# This file is part of the micropython-esp32-ulp project,
+# https://github.com/micropython/micropython-esp32-ulp
+#
+# SPDX-FileCopyrightText: 2018-2023, the micropython-esp32-ulp authors, see AUTHORS file.
+# SPDX-License-Identifier: MIT
+
 """
 Address / Register definitions for the ESP32-S3 SoC
 """
diff --git a/esp32_ulp/util.py b/esp32_ulp/util.py
index 53cec65..78e7c85 100644
--- a/esp32_ulp/util.py
+++ b/esp32_ulp/util.py
@@ -1,3 +1,10 @@
+#
+# This file is part of the micropython-esp32-ulp project,
+# https://github.com/micropython/micropython-esp32-ulp
+#
+# SPDX-FileCopyrightText: 2018-2023, the micropython-esp32-ulp authors, see AUTHORS file.
+# SPDX-License-Identifier: MIT
+
 DEBUG = False
 
 import gc
diff --git a/examples/blink.py b/examples/blink.py
index 04e3b8f..3c43883 100644
--- a/examples/blink.py
+++ b/examples/blink.py
@@ -1,3 +1,10 @@
+#
+# This file is part of the micropython-esp32-ulp project,
+# https://github.com/micropython/micropython-esp32-ulp
+#
+# SPDX-FileCopyrightText: 2018-2023, the micropython-esp32-ulp authors, see AUTHORS file.
+# SPDX-License-Identifier: MIT
+
 """
 Example for: ESP32
 
diff --git a/examples/blink_s2.py b/examples/blink_s2.py
index 86b0c3c..2bdeccc 100644
--- a/examples/blink_s2.py
+++ b/examples/blink_s2.py
@@ -1,3 +1,10 @@
+#
+# This file is part of the micropython-esp32-ulp project,
+# https://github.com/micropython/micropython-esp32-ulp
+#
+# SPDX-FileCopyrightText: 2018-2023, the micropython-esp32-ulp authors, see AUTHORS file.
+# SPDX-License-Identifier: MIT
+
 """
 Example for: ESP32-S2 and ESP32-S3
 
diff --git a/examples/counter.py b/examples/counter.py
index e3a72b5..6029bbd 100644
--- a/examples/counter.py
+++ b/examples/counter.py
@@ -1,3 +1,10 @@
+#
+# This file is part of the micropython-esp32-ulp project,
+# https://github.com/micropython/micropython-esp32-ulp
+#
+# SPDX-FileCopyrightText: 2018-2023, the micropython-esp32-ulp authors, see AUTHORS file.
+# SPDX-License-Identifier: MIT
+
 """
 Example for: ESP32
 
diff --git a/examples/counter_s2.py b/examples/counter_s2.py
index 8119db7..a5abbf9 100644
--- a/examples/counter_s2.py
+++ b/examples/counter_s2.py
@@ -1,3 +1,10 @@
+#
+# This file is part of the micropython-esp32-ulp project,
+# https://github.com/micropython/micropython-esp32-ulp
+#
+# SPDX-FileCopyrightText: 2018-2023, the micropython-esp32-ulp authors, see AUTHORS file.
+# SPDX-License-Identifier: MIT
+
 """
 Example for: ESP32-S2 and ESP32-S3
 
diff --git a/examples/readgpio.py b/examples/readgpio.py
index 8a8fca7..944f1c2 100644
--- a/examples/readgpio.py
+++ b/examples/readgpio.py
@@ -1,3 +1,10 @@
+#
+# This file is part of the micropython-esp32-ulp project,
+# https://github.com/micropython/micropython-esp32-ulp
+#
+# SPDX-FileCopyrightText: 2018-2023, the micropython-esp32-ulp authors, see AUTHORS file.
+# SPDX-License-Identifier: MIT
+
 """
 Example for: ESP32
 
diff --git a/examples/readgpio_s2.py b/examples/readgpio_s2.py
index 60ae43e..91614e3 100644
--- a/examples/readgpio_s2.py
+++ b/examples/readgpio_s2.py
@@ -1,3 +1,10 @@
+#
+# This file is part of the micropython-esp32-ulp project,
+# https://github.com/micropython/micropython-esp32-ulp
+#
+# SPDX-FileCopyrightText: 2018-2023, the micropython-esp32-ulp authors, see AUTHORS file.
+# SPDX-License-Identifier: MIT
+
 """
 Example for: ESP32-S2
 
diff --git a/examples/readgpio_s3.py b/examples/readgpio_s3.py
index b1f9779..d5645cd 100644
--- a/examples/readgpio_s3.py
+++ b/examples/readgpio_s3.py
@@ -1,3 +1,10 @@
+#
+# This file is part of the micropython-esp32-ulp project,
+# https://github.com/micropython/micropython-esp32-ulp
+#
+# SPDX-FileCopyrightText: 2018-2023, the micropython-esp32-ulp authors, see AUTHORS file.
+# SPDX-License-Identifier: MIT
+
 """
 Example for: ESP32-S3
 
diff --git a/setup.py b/setup.py
index 02fc461..4eab8ff 100644
--- a/setup.py
+++ b/setup.py
@@ -1,3 +1,10 @@
+#
+# This file is part of the micropython-esp32-ulp project,
+# https://github.com/micropython/micropython-esp32-ulp
+#
+# SPDX-FileCopyrightText: 2018-2023, the micropython-esp32-ulp authors, see AUTHORS file.
+# SPDX-License-Identifier: MIT
+
 import re
 from setuptools import setup
 import sdist_upip
diff --git a/tests/00_unit_tests.sh b/tests/00_unit_tests.sh
index 262b759..0a01933 100755
--- a/tests/00_unit_tests.sh
+++ b/tests/00_unit_tests.sh
@@ -1,4 +1,10 @@
 #!/bin/bash
+#
+# This file is part of the micropython-esp32-ulp project,
+# https://github.com/micropython/micropython-esp32-ulp
+#
+# SPDX-FileCopyrightText: 2018-2023, the micropython-esp32-ulp authors, see AUTHORS file.
+# SPDX-License-Identifier: MIT
 
 # export PYTHONPATH=.:$PYTHONPATH
 
diff --git a/tests/01_compat_tests.sh b/tests/01_compat_tests.sh
index 3729292..0732d34 100755
--- a/tests/01_compat_tests.sh
+++ b/tests/01_compat_tests.sh
@@ -1,4 +1,10 @@
 #!/bin/bash
+#
+# This file is part of the micropython-esp32-ulp project,
+# https://github.com/micropython/micropython-esp32-ulp
+#
+# SPDX-FileCopyrightText: 2018-2023, the micropython-esp32-ulp authors, see AUTHORS file.
+# SPDX-License-Identifier: MIT
 
 # export PYTHONPATH=.:$PYTHONPATH
 
diff --git a/tests/02_compat_rtc_tests.sh b/tests/02_compat_rtc_tests.sh
index 467ccae..1e6a2d1 100755
--- a/tests/02_compat_rtc_tests.sh
+++ b/tests/02_compat_rtc_tests.sh
@@ -1,4 +1,10 @@
 #!/bin/bash
+#
+# This file is part of the micropython-esp32-ulp project,
+# https://github.com/micropython/micropython-esp32-ulp
+#
+# SPDX-FileCopyrightText: 2018-2023, the micropython-esp32-ulp authors, see AUTHORS file.
+# SPDX-License-Identifier: MIT
 
 # export PYTHONPATH=.:$PYTHONPATH
 
diff --git a/tests/03_disassembler_tests.sh b/tests/03_disassembler_tests.sh
index 2ecc7a0..c32a201 100755
--- a/tests/03_disassembler_tests.sh
+++ b/tests/03_disassembler_tests.sh
@@ -1,4 +1,10 @@
 #!/bin/bash
+#
+# This file is part of the micropython-esp32-ulp project,
+# https://github.com/micropython/micropython-esp32-ulp
+#
+# SPDX-FileCopyrightText: 2018-2023, the micropython-esp32-ulp authors, see AUTHORS file.
+# SPDX-License-Identifier: MIT
 
 set -e
 
diff --git a/tests/assemble.py b/tests/assemble.py
index c17bbce..cfd1baa 100644
--- a/tests/assemble.py
+++ b/tests/assemble.py
@@ -1,3 +1,10 @@
+#
+# This file is part of the micropython-esp32-ulp project,
+# https://github.com/micropython/micropython-esp32-ulp
+#
+# SPDX-FileCopyrightText: 2018-2023, the micropython-esp32-ulp authors, see AUTHORS file.
+# SPDX-License-Identifier: MIT
+
 from esp32_ulp.assemble import Assembler, TEXT, DATA, BSS, REL, ABS
 from esp32_ulp.assemble import SymbolTable
 from esp32_ulp.nocomment import remove_comments
diff --git a/tests/compat/alu.S b/tests/compat/alu.S
index 02f873e..ddb5110 100644
--- a/tests/compat/alu.S
+++ b/tests/compat/alu.S
@@ -1,3 +1,10 @@
+#
+# This file is part of the micropython-esp32-ulp project,
+# https://github.com/micropython/micropython-esp32-ulp
+#
+# SPDX-FileCopyrightText: 2018-2023, the micropython-esp32-ulp authors, see AUTHORS file.
+# SPDX-License-Identifier: MIT
+
             .text
             
             and r1, r2, r3
diff --git a/tests/compat/expr.S b/tests/compat/expr.S
index 40a0592..a92b1c6 100644
--- a/tests/compat/expr.S
+++ b/tests/compat/expr.S
@@ -1,3 +1,10 @@
+#
+# This file is part of the micropython-esp32-ulp project,
+# https://github.com/micropython/micropython-esp32-ulp
+#
+# SPDX-FileCopyrightText: 2018-2023, the micropython-esp32-ulp authors, see AUTHORS file.
+# SPDX-License-Identifier: MIT
+
 # common example of real world code using expressions
   .set adc_channel, 6
 
diff --git a/tests/compat/fixes.S b/tests/compat/fixes.S
index 3b33a78..b3dc648 100644
--- a/tests/compat/fixes.S
+++ b/tests/compat/fixes.S
@@ -1,3 +1,10 @@
+#
+# This file is part of the micropython-esp32-ulp project,
+# https://github.com/micropython/micropython-esp32-ulp
+#
+# SPDX-FileCopyrightText: 2018-2023, the micropython-esp32-ulp authors, see AUTHORS file.
+# SPDX-License-Identifier: MIT
+
 # This file tests various fixes to the assembler,
 # to ensure the binary output matches that of binutils.
 # a) support for left-aligned directives (e.g. .set without preceding whitespace)
diff --git a/tests/compat/io.S b/tests/compat/io.S
index ea66a87..47cab33 100644
--- a/tests/compat/io.S
+++ b/tests/compat/io.S
@@ -1,3 +1,10 @@
+#
+# This file is part of the micropython-esp32-ulp project,
+# https://github.com/micropython/micropython-esp32-ulp
+#
+# SPDX-FileCopyrightText: 2018-2023, the micropython-esp32-ulp authors, see AUTHORS file.
+# SPDX-License-Identifier: MIT
+
             .text
 
             reg_rd 0x3ff48000, 7, 0
diff --git a/tests/compat/jumps.S b/tests/compat/jumps.S
index ebf0543..27283e1 100644
--- a/tests/compat/jumps.S
+++ b/tests/compat/jumps.S
@@ -1,3 +1,10 @@
+#
+# This file is part of the micropython-esp32-ulp project,
+# https://github.com/micropython/micropython-esp32-ulp
+#
+# SPDX-FileCopyrightText: 2018-2023, the micropython-esp32-ulp authors, see AUTHORS file.
+# SPDX-License-Identifier: MIT
+
   .text
   .set const, 3
   .global const  # exporting symbol is required for binutils, not important for micropython-esp32-ulp
diff --git a/tests/compat/loadstore.esp32s2.S b/tests/compat/loadstore.esp32s2.S
index d0c032f..cb45c42 100644
--- a/tests/compat/loadstore.esp32s2.S
+++ b/tests/compat/loadstore.esp32s2.S
@@ -1,3 +1,10 @@
+#
+# This file is part of the micropython-esp32-ulp project,
+# https://github.com/micropython/micropython-esp32-ulp
+#
+# SPDX-FileCopyrightText: 2018-2023, the micropython-esp32-ulp authors, see AUTHORS file.
+# SPDX-License-Identifier: MIT
+
 .set  offs, 0x20
 .set  lab1, 0x01
 
diff --git a/tests/compat/memory.S b/tests/compat/memory.S
index d8d57b8..d7ec2a2 100644
--- a/tests/compat/memory.S
+++ b/tests/compat/memory.S
@@ -1,3 +1,10 @@
+#
+# This file is part of the micropython-esp32-ulp project,
+# https://github.com/micropython/micropython-esp32-ulp
+#
+# SPDX-FileCopyrightText: 2018-2023, the micropython-esp32-ulp authors, see AUTHORS file.
+# SPDX-License-Identifier: MIT
+
             .text
 
             ld r0, r1, 0
diff --git a/tests/compat/preprocess_simple.S b/tests/compat/preprocess_simple.S
index b6a61e8..17ea020 100644
--- a/tests/compat/preprocess_simple.S
+++ b/tests/compat/preprocess_simple.S
@@ -1,3 +1,10 @@
+#
+# This file is part of the micropython-esp32-ulp project,
+# https://github.com/micropython/micropython-esp32-ulp
+#
+# SPDX-FileCopyrightText: 2018-2023, the micropython-esp32-ulp authors, see AUTHORS file.
+# SPDX-License-Identifier: MIT
+
 #define GPIO 2
 #define BASE 0x100
 #define ADDR (BASE + GPIO)
diff --git a/tests/compat/reg.esp32.S b/tests/compat/reg.esp32.S
index e9b1a14..39ce461 100644
--- a/tests/compat/reg.esp32.S
+++ b/tests/compat/reg.esp32.S
@@ -1,3 +1,10 @@
+#
+# This file is part of the micropython-esp32-ulp project,
+# https://github.com/micropython/micropython-esp32-ulp
+#
+# SPDX-FileCopyrightText: 2018-2023, the micropython-esp32-ulp authors, see AUTHORS file.
+# SPDX-License-Identifier: MIT
+
 #include "soc/rtc_cntl_reg.h"
 #include "soc/soc_ulp.h"
 
diff --git a/tests/compat/reg.esp32s2.S b/tests/compat/reg.esp32s2.S
index c8c9920..cd6b072 100644
--- a/tests/compat/reg.esp32s2.S
+++ b/tests/compat/reg.esp32s2.S
@@ -1,3 +1,10 @@
+#
+# This file is part of the micropython-esp32-ulp project,
+# https://github.com/micropython/micropython-esp32-ulp
+#
+# SPDX-FileCopyrightText: 2018-2023, the micropython-esp32-ulp authors, see AUTHORS file.
+# SPDX-License-Identifier: MIT
+
 #include "soc/rtc_cntl_reg.h"
 #include "soc/soc_ulp.h"
 
diff --git a/tests/compat/sections.S b/tests/compat/sections.S
index ca448b8..50d41cc 100644
--- a/tests/compat/sections.S
+++ b/tests/compat/sections.S
@@ -1,3 +1,10 @@
+#
+# This file is part of the micropython-esp32-ulp project,
+# https://github.com/micropython/micropython-esp32-ulp
+#
+# SPDX-FileCopyrightText: 2018-2023, the micropython-esp32-ulp authors, see AUTHORS file.
+# SPDX-License-Identifier: MIT
+
             .text
 
             nop
diff --git a/tests/compat/sleep.S b/tests/compat/sleep.S
index 7638e59..132e3bf 100644
--- a/tests/compat/sleep.S
+++ b/tests/compat/sleep.S
@@ -1,3 +1,10 @@
+#
+# This file is part of the micropython-esp32-ulp project,
+# https://github.com/micropython/micropython-esp32-ulp
+#
+# SPDX-FileCopyrightText: 2018-2023, the micropython-esp32-ulp authors, see AUTHORS file.
+# SPDX-License-Identifier: MIT
+
             .text
 
             nop
diff --git a/tests/compat/symbols.S b/tests/compat/symbols.S
index 359fa15..92fa34c 100644
--- a/tests/compat/symbols.S
+++ b/tests/compat/symbols.S
@@ -1,3 +1,10 @@
+#
+# This file is part of the micropython-esp32-ulp project,
+# https://github.com/micropython/micropython-esp32-ulp
+#
+# SPDX-FileCopyrightText: 2018-2023, the micropython-esp32-ulp authors, see AUTHORS file.
+# SPDX-License-Identifier: MIT
+
             .text
 
             .set constant42, 42
diff --git a/tests/decode.py b/tests/decode.py
index 916bb95..eb74b95 100644
--- a/tests/decode.py
+++ b/tests/decode.py
@@ -1,3 +1,10 @@
+#
+# This file is part of the micropython-esp32-ulp project,
+# https://github.com/micropython/micropython-esp32-ulp
+#
+# SPDX-FileCopyrightText: 2018-2023, the micropython-esp32-ulp authors, see AUTHORS file.
+# SPDX-License-Identifier: MIT
+
 from tools.decode import decode_instruction, get_instruction_fields
 import esp32_ulp.opcodes as opcodes
 import ubinascii
diff --git a/tests/decode_s2.py b/tests/decode_s2.py
index 5fc2da6..52838ca 100644
--- a/tests/decode_s2.py
+++ b/tests/decode_s2.py
@@ -1,3 +1,10 @@
+#
+# This file is part of the micropython-esp32-ulp project,
+# https://github.com/micropython/micropython-esp32-ulp
+#
+# SPDX-FileCopyrightText: 2018-2023, the micropython-esp32-ulp authors, see AUTHORS file.
+# SPDX-License-Identifier: MIT
+
 from tools.decode_s2 import decode_instruction, get_instruction_fields
 import esp32_ulp.opcodes_s2 as opcodes
 import ubinascii
diff --git a/tests/definesdb.py b/tests/definesdb.py
index 5e2100c..975c288 100644
--- a/tests/definesdb.py
+++ b/tests/definesdb.py
@@ -1,3 +1,10 @@
+#
+# This file is part of the micropython-esp32-ulp project,
+# https://github.com/micropython/micropython-esp32-ulp
+#
+# SPDX-FileCopyrightText: 2018-2023, the micropython-esp32-ulp authors, see AUTHORS file.
+# SPDX-License-Identifier: MIT
+
 import os
 
 from esp32_ulp.definesdb import DefinesDB, DBNAME
diff --git a/tests/fixtures/all_opcodes.esp32.S b/tests/fixtures/all_opcodes.esp32.S
index 1710bc9..66d7763 100644
--- a/tests/fixtures/all_opcodes.esp32.S
+++ b/tests/fixtures/all_opcodes.esp32.S
@@ -1,3 +1,10 @@
+#
+# This file is part of the micropython-esp32-ulp project,
+# https://github.com/micropython/micropython-esp32-ulp
+#
+# SPDX-FileCopyrightText: 2018-2023, the micropython-esp32-ulp authors, see AUTHORS file.
+# SPDX-License-Identifier: MIT
+
 .data
 empty: .long 0
 magic: .long 0xc0decafe
diff --git a/tests/fixtures/all_opcodes.esp32s2.S b/tests/fixtures/all_opcodes.esp32s2.S
index 7483840..c53973c 100644
--- a/tests/fixtures/all_opcodes.esp32s2.S
+++ b/tests/fixtures/all_opcodes.esp32s2.S
@@ -1,3 +1,10 @@
+#
+# This file is part of the micropython-esp32-ulp project,
+# https://github.com/micropython/micropython-esp32-ulp
+#
+# SPDX-FileCopyrightText: 2018-2023, the micropython-esp32-ulp authors, see AUTHORS file.
+# SPDX-License-Identifier: MIT
+
 .data
 empty: .long 0
 magic: .long 0xc0decafe
diff --git a/tests/fixtures/incl.h b/tests/fixtures/incl.h
index 712aa7c..1c1e033 100644
--- a/tests/fixtures/incl.h
+++ b/tests/fixtures/incl.h
@@ -1,3 +1,10 @@
+#
+# This file is part of the micropython-esp32-ulp project,
+# https://github.com/micropython/micropython-esp32-ulp
+#
+# SPDX-FileCopyrightText: 2018-2023, the micropython-esp32-ulp authors, see AUTHORS file.
+# SPDX-License-Identifier: MIT
+
 #define CONST1 42
 #define MACRO(x,y) x+y
 #define MULTI_LINE abc \
diff --git a/tests/fixtures/incl2.h b/tests/fixtures/incl2.h
index d19aeba..fa64ef0 100644
--- a/tests/fixtures/incl2.h
+++ b/tests/fixtures/incl2.h
@@ -1,2 +1,9 @@
+#
+# This file is part of the micropython-esp32-ulp project,
+# https://github.com/micropython/micropython-esp32-ulp
+#
+# SPDX-FileCopyrightText: 2018-2023, the micropython-esp32-ulp authors, see AUTHORS file.
+# SPDX-License-Identifier: MIT
+
 #define CONST2 123
 #define CONST3 777
diff --git a/tests/link.py b/tests/link.py
index 8a301f4..09673b3 100644
--- a/tests/link.py
+++ b/tests/link.py
@@ -1,3 +1,10 @@
+#
+# This file is part of the micropython-esp32-ulp project,
+# https://github.com/micropython/micropython-esp32-ulp
+#
+# SPDX-FileCopyrightText: 2018-2023, the micropython-esp32-ulp authors, see AUTHORS file.
+# SPDX-License-Identifier: MIT
+
 from esp32_ulp.link import make_binary
 
 
diff --git a/tests/nocomment.py b/tests/nocomment.py
index 8b476d0..daa6406 100644
--- a/tests/nocomment.py
+++ b/tests/nocomment.py
@@ -1,3 +1,10 @@
+#
+# This file is part of the micropython-esp32-ulp project,
+# https://github.com/micropython/micropython-esp32-ulp
+#
+# SPDX-FileCopyrightText: 2018-2023, the micropython-esp32-ulp authors, see AUTHORS file.
+# SPDX-License-Identifier: MIT
+
 from esp32_ulp.nocomment import remove_comments
 
 ORIG = """\
diff --git a/tests/opcodes.py b/tests/opcodes.py
index 576c840..3dc7453 100644
--- a/tests/opcodes.py
+++ b/tests/opcodes.py
@@ -1,3 +1,10 @@
+#
+# This file is part of the micropython-esp32-ulp project,
+# https://github.com/micropython/micropython-esp32-ulp
+#
+# SPDX-FileCopyrightText: 2018-2023, the micropython-esp32-ulp authors, see AUTHORS file.
+# SPDX-License-Identifier: MIT
+
 from uctypes import UINT32, BFUINT32, BF_POS, BF_LEN
 from esp32_ulp.opcodes import make_ins, make_ins_struct_def
 from esp32_ulp.opcodes import get_reg, get_imm, get_cond, arg_qualify, eval_arg, ARG, REG, IMM, SYM, COND
diff --git a/tests/opcodes_s2.py b/tests/opcodes_s2.py
index 2c724c3..4525049 100644
--- a/tests/opcodes_s2.py
+++ b/tests/opcodes_s2.py
@@ -1,3 +1,10 @@
+#
+# This file is part of the micropython-esp32-ulp project,
+# https://github.com/micropython/micropython-esp32-ulp
+#
+# SPDX-FileCopyrightText: 2018-2023, the micropython-esp32-ulp authors, see AUTHORS file.
+# SPDX-License-Identifier: MIT
+
 from uctypes import UINT32, BFUINT32, BF_POS, BF_LEN
 from esp32_ulp.opcodes_s2 import make_ins, make_ins_struct_def
 from esp32_ulp.opcodes_s2 import get_reg, get_imm, get_cond, arg_qualify, eval_arg, ARG, REG, IMM, SYM, COND
diff --git a/tests/preprocess.py b/tests/preprocess.py
index be7cf61..e914577 100644
--- a/tests/preprocess.py
+++ b/tests/preprocess.py
@@ -1,3 +1,10 @@
+#
+# This file is part of the micropython-esp32-ulp project,
+# https://github.com/micropython/micropython-esp32-ulp
+#
+# SPDX-FileCopyrightText: 2018-2023, the micropython-esp32-ulp authors, see AUTHORS file.
+# SPDX-License-Identifier: MIT
+
 import os
 
 from esp32_ulp.preprocess import Preprocessor
diff --git a/tests/util.py b/tests/util.py
index e42ff15..6aadc8b 100644
--- a/tests/util.py
+++ b/tests/util.py
@@ -1,3 +1,10 @@
+#
+# This file is part of the micropython-esp32-ulp project,
+# https://github.com/micropython/micropython-esp32-ulp
+#
+# SPDX-FileCopyrightText: 2018-2023, the micropython-esp32-ulp authors, see AUTHORS file.
+# SPDX-License-Identifier: MIT
+
 import os
 from esp32_ulp.util import split_tokens, validate_expression, file_exists
 
diff --git a/tools/decode.py b/tools/decode.py
index 3aaf095..fb93e73 100644
--- a/tools/decode.py
+++ b/tools/decode.py
@@ -1,3 +1,10 @@
+#
+# This file is part of the micropython-esp32-ulp project,
+# https://github.com/micropython/micropython-esp32-ulp
+#
+# SPDX-FileCopyrightText: 2018-2023, the micropython-esp32-ulp authors, see AUTHORS file.
+# SPDX-License-Identifier: MIT
+
 import esp32_ulp.opcodes as opcodes
 
 
diff --git a/tools/decode_s2.py b/tools/decode_s2.py
index de3b3c7..f25c5b0 100644
--- a/tools/decode_s2.py
+++ b/tools/decode_s2.py
@@ -1,3 +1,10 @@
+#
+# This file is part of the micropython-esp32-ulp project,
+# https://github.com/micropython/micropython-esp32-ulp
+#
+# SPDX-FileCopyrightText: 2018-2023, the micropython-esp32-ulp authors, see AUTHORS file.
+# SPDX-License-Identifier: MIT
+
 import esp32_ulp.opcodes_s2 as opcodes
 
 
diff --git a/tools/disassemble.py b/tools/disassemble.py
index 442c8f3..774771f 100644
--- a/tools/disassemble.py
+++ b/tools/disassemble.py
@@ -1,3 +1,10 @@
+#
+# This file is part of the micropython-esp32-ulp project,
+# https://github.com/micropython/micropython-esp32-ulp
+#
+# SPDX-FileCopyrightText: 2018-2023, the micropython-esp32-ulp authors, see AUTHORS file.
+# SPDX-License-Identifier: MIT
+
 from uctypes import struct, addressof, LITTLE_ENDIAN, UINT16, UINT32
 import ubinascii
 import sys
diff --git a/tools/genpkgjson.py b/tools/genpkgjson.py
index f41dcaf..7572f85 100644
--- a/tools/genpkgjson.py
+++ b/tools/genpkgjson.py
@@ -1,3 +1,10 @@
+#
+# This file is part of the micropython-esp32-ulp project,
+# https://github.com/micropython/micropython-esp32-ulp
+#
+# SPDX-FileCopyrightText: 2018-2023, the micropython-esp32-ulp authors, see AUTHORS file.
+# SPDX-License-Identifier: MIT
+
 """
 Tool for generating package.json for the MIP package manager