diff --git a/src/basic/gunicode.c b/src/basic/gunicode.c
index c51b1a7a18..02637d74e9 100644
--- a/src/basic/gunicode.c
+++ b/src/basic/gunicode.c
@@ -1,3 +1,4 @@
+/* SPDX-License-Identifier: LGPL-2.1+ */
 /* gunicode.c - Unicode manipulation functions
  *
  *  Copyright (C) 1999, 2000 Tom Tromey
diff --git a/src/basic/gunicode.h b/src/basic/gunicode.h
index a16b7b6ff1..765077db83 100644
--- a/src/basic/gunicode.h
+++ b/src/basic/gunicode.h
@@ -1,10 +1,10 @@
-#pragma once
-
+/* SPDX-License-Identifier: LGPL-2.1+ */
 /* gunicode.h - Unicode manipulation functions
  *
  *  Copyright (C) 1999, 2000 Tom Tromey
  *  Copyright © 2000, 2005 Red Hat, Inc.
  */
+#pragma once
 
 #include <stdbool.h>
 #include <stdint.h>
diff --git a/src/basic/siphash24.c b/src/basic/siphash24.c
index 61180819b1..7c61eb145d 100644
--- a/src/basic/siphash24.c
+++ b/src/basic/siphash24.c
@@ -1,3 +1,5 @@
+/* SPDX-License-Identifier: CC0-1.0 */
+
 /*
    SipHash reference C implementation
 
@@ -10,7 +12,7 @@
    worldwide. This software is distributed without any warranty.
 
    You should have received a copy of the CC0 Public Domain Dedication along with
-   this software. If not, see <http://creativecommons.org/publicdomain/zero/1.0/>.
+   this software. If not, see <https://creativecommons.org/publicdomain/zero/1.0/>.
 
    (Minimal changes made by Lennart Poettering, to make clean for inclusion in systemd)
    (Refactored by Tom Gundersen to split up in several functions and follow systemd
diff --git a/src/basic/siphash24.h b/src/basic/siphash24.h
index fe43256882..90a6de00e4 100644
--- a/src/basic/siphash24.h
+++ b/src/basic/siphash24.h
@@ -1,3 +1,5 @@
+/* SPDX-License-Identifier: CC0-1.0 */
+
 #pragma once
 
 #include <inttypes.h>
diff --git a/src/boot/efi/sha256.c b/src/boot/efi/sha256.c
index 40da636dc7..005e1902d4 100644
--- a/src/boot/efi/sha256.c
+++ b/src/boot/efi/sha256.c
@@ -1,3 +1,5 @@
+/* SPDX-License-Identifier: LGPL-2.1+ */
+
 /* Stolen from glibc and converted to UEFI style. In glibc it comes with the following copyright blurb: */
 
 /* Functions to compute SHA256 message digest of files or memory blocks.
diff --git a/src/shared/initreq.h b/src/shared/initreq.h
index 1d7ff81df1..1bf5b8edd7 100644
--- a/src/shared/initreq.h
+++ b/src/shared/initreq.h
@@ -1,3 +1,4 @@
+/* SPDX-License-Identifier: LGPL-2+ */
 /*
  * initreq.h	Interface to talk to init through /dev/initctl.
  *
diff --git a/src/shared/linux/nl80211.h b/src/shared/linux/nl80211.h
index b065c1fe4d..65edfff1ca 100644
--- a/src/shared/linux/nl80211.h
+++ b/src/shared/linux/nl80211.h
@@ -1,3 +1,5 @@
+/* SPDX-License-Identifier: MIT */
+
 #ifndef __LINUX_NL80211_H
 #define __LINUX_NL80211_H
 /*