license: add header to files where it was missing

diff --git a/messages/CMakeLists.txt b/messages/CMakeLists.txt
index a503242..a37cd0d 100644
--- a/messages/CMakeLists.txt
+++ b/messages/CMakeLists.txt
@@ -1,3 +1,5 @@
+# SPDX-License-Identifier: Apache-2.0
+
 set(PROTO_FILES
   hww.proto
   backup.proto
diff --git a/messages/keystore.proto b/messages/keystore.proto
index d6d5641..4f63cd3 100644
--- a/messages/keystore.proto
+++ b/messages/keystore.proto
@@ -1,3 +1,5 @@
+// SPDX-License-Identifier: Apache-2.0
+
 // This function can be used to get an identifying xpub at the keypath m/4541509'/1112098098'"
 // The keypath argument has to be m/4541509'/1112098098'
 
diff --git a/messages/perform_attestation.proto b/messages/perform_attestation.proto
index 50d0d48..db7f399 100644
--- a/messages/perform_attestation.proto
+++ b/messages/perform_attestation.proto
@@ -1,3 +1,4 @@
+// SPDX-License-Identifier: Apache-2.0
 
 syntax = "proto3";
 package shiftcrypto.bitbox02;
diff --git a/py/Makefile b/py/Makefile
index 4fc0643..bd513e5 100644
--- a/py/Makefile
+++ b/py/Makefile
@@ -1,3 +1,5 @@
+# SPDX-License-Identifier: Apache-2.0
+
 all:
 	${MAKE} -C bitbox02
 
diff --git a/py/bitbox02/bitbox02/__init__.py b/py/bitbox02/bitbox02/__init__.py
index fd035dc..67c6f63 100644
--- a/py/bitbox02/bitbox02/__init__.py
+++ b/py/bitbox02/bitbox02/__init__.py
@@ -1,3 +1,5 @@
+# SPDX-License-Identifier: Apache-2.0
+
 """
 This file re-exports all symbols from the nested bitbox02 subpackage.
 
diff --git a/py/u2f/bitbox02.py b/py/u2f/bitbox02.py
index 07c04f5..9f6a149 100644
--- a/py/u2f/bitbox02.py
+++ b/py/u2f/bitbox02.py
@@ -1,3 +1,5 @@
+# SPDX-License-Identifier: Apache-2.0
+
 """Helpers for doing U2F with bitbox02"""
 
 from typing import Tuple
diff --git a/releases/build.sh b/releases/build.sh
index 5858bb0..88193cd 100755
--- a/releases/build.sh
+++ b/releases/build.sh
@@ -1,4 +1,5 @@
 #!/bin/bash -e
+# SPDX-License-Identifier: Apache-2.0
 
 # To maintainers: keep this script straight forward to follow and
 # review.
diff --git a/scripts/CMakeLists.txt b/scripts/CMakeLists.txt
index 0a68e89..ab8e667 100644
--- a/scripts/CMakeLists.txt
+++ b/scripts/CMakeLists.txt
@@ -1,3 +1,5 @@
+# SPDX-License-Identifier: Apache-2.0
+
 if(PYTHONINTERP_FOUND)
   # This template flashes with an offset
   foreach(target ${FIRMWARES})
diff --git a/scripts/graphics/Makefile b/scripts/graphics/Makefile
index a8fd9ba..a44331e 100644
--- a/scripts/graphics/Makefile
+++ b/scripts/graphics/Makefile
@@ -1,3 +1,5 @@
+# SPDX-License-Identifier: Apache-2.0
+
 SOURCES=bb02_logo.png bb02_btc_logo.png bb02_multi_logo.png
 
 %.pbm: %.png
diff --git a/scripts/graphics/convert.py b/scripts/graphics/convert.py
index bf70c0c..0f2704d 100755
--- a/scripts/graphics/convert.py
+++ b/scripts/graphics/convert.py
@@ -1,4 +1,6 @@
 #!/usr/bin/env python3
+# SPDX-License-Identifier: Apache-2.0
+
 """Helper script to convert images to c source code"""
 import argparse
 
diff --git a/src/rust/bitbox02-rust/src/hww/api/change_password.rs b/src/rust/bitbox02-rust/src/hww/api/change_password.rs
index d3c2754..bb96998 100644
--- a/src/rust/bitbox02-rust/src/hww/api/change_password.rs
+++ b/src/rust/bitbox02-rust/src/hww/api/change_password.rs
@@ -1,3 +1,5 @@
+// SPDX-License-Identifier: Apache-2.0
+
 use super::Error;
 use crate::pb;
 
diff --git a/src/rust/util/src/log.rs b/src/rust/util/src/log.rs
index d50d6d9..6f497c4 100644
--- a/src/rust/util/src/log.rs
+++ b/src/rust/util/src/log.rs
@@ -1,3 +1,5 @@
+// SPDX-License-Identifier: Apache-2.0
+
 // Re-export rtt_target so that it is available to the macro user
 #[cfg(all(feature = "rtt", target_os = "none"))]
 pub use ::rtt_target;
diff --git a/src/u2f/u2f_app.c b/src/u2f/u2f_app.c
index f424160..2fed797 100644
--- a/src/u2f/u2f_app.c
+++ b/src/u2f/u2f_app.c
@@ -1,3 +1,5 @@
+// SPDX-License-Identifier: Apache-2.0
+
 #include "u2f_app.h"
 
 #include <hardfault.h>
diff --git a/src/ui/graphics/graphics.c b/src/ui/graphics/graphics.c
index a1510d1..502c56b 100644
--- a/src/ui/graphics/graphics.c
+++ b/src/ui/graphics/graphics.c
@@ -1,3 +1,5 @@
+// SPDX-License-Identifier: Apache-2.0
+
 #include "graphics.h"
 
 #include <screen.h>
diff --git a/src/usb/u2f/u2f_keys.h b/src/usb/u2f/u2f_keys.h
index 6536913..b2cce03 100644
--- a/src/usb/u2f/u2f_keys.h
+++ b/src/usb/u2f/u2f_keys.h
@@ -1,3 +1,5 @@
+// SPDX-License-Identifier: Apache-2.0
+
 #ifndef __U2F_KEYS_H_INCLUDED__
 #define __U2F_KEYS_H_INCLUDED__
 
diff --git a/src/version.h.in b/src/version.h.in
index 3462b59..0631c53 100644
--- a/src/version.h.in
+++ b/src/version.h.in
@@ -1,3 +1,5 @@
+// SPDX-License-Identifier: Apache-2.0
+
 #ifndef VERSION_H
 #define VERSION_H