diff --git a/newlib/libc/sys/rtems/include/net/if.h b/newlib/libc/sys/rtems/include/net/if.h
index 04f828e44..463bdf4a2 100644
--- a/newlib/libc/sys/rtems/include/net/if.h
+++ b/newlib/libc/sys/rtems/include/net/if.h
@@ -1,4 +1,6 @@
 /*-
+ * SPDX-License-Identifier: BSD-3-Clause
+ *
  * Copyright (c) 1982, 1986, 1989, 1993
  *	The Regents of the University of California.  All rights reserved.
  *
diff --git a/newlib/libc/sys/rtems/include/netinet/in.h b/newlib/libc/sys/rtems/include/netinet/in.h
index 390cf8cd3..479cb4f3a 100644
--- a/newlib/libc/sys/rtems/include/netinet/in.h
+++ b/newlib/libc/sys/rtems/include/netinet/in.h
@@ -1,4 +1,6 @@
 /*-
+ * SPDX-License-Identifier: BSD-3-Clause
+ *
  * Copyright (c) 1982, 1986, 1990, 1993
  *	The Regents of the University of California.  All rights reserved.
  *
diff --git a/newlib/libc/sys/rtems/include/netinet/tcp.h b/newlib/libc/sys/rtems/include/netinet/tcp.h
index 4fd597f36..7eb4e9afd 100644
--- a/newlib/libc/sys/rtems/include/netinet/tcp.h
+++ b/newlib/libc/sys/rtems/include/netinet/tcp.h
@@ -1,4 +1,6 @@
 /*-
+ * SPDX-License-Identifier: BSD-3-Clause
+ *
  * Copyright (c) 1982, 1986, 1993
  *	The Regents of the University of California.  All rights reserved.
  *
diff --git a/newlib/libc/sys/rtems/include/netinet6/in6.h b/newlib/libc/sys/rtems/include/netinet6/in6.h
index f9207e847..99ac803b8 100644
--- a/newlib/libc/sys/rtems/include/netinet6/in6.h
+++ b/newlib/libc/sys/rtems/include/netinet6/in6.h
@@ -1,4 +1,6 @@
 /*-
+ * SPDX-License-Identifier: BSD-3-Clause
+ *
  * Copyright (C) 1995, 1996, 1997, and 1998 WIDE Project.
  * All rights reserved.
  *
diff --git a/newlib/libc/sys/rtems/include/sys/_iovec.h b/newlib/libc/sys/rtems/include/sys/_iovec.h
index 7f53bb220..31dd3c4cd 100644
--- a/newlib/libc/sys/rtems/include/sys/_iovec.h
+++ b/newlib/libc/sys/rtems/include/sys/_iovec.h
@@ -1,4 +1,6 @@
 /*-
+ * SPDX-License-Identifier: BSD-3-Clause
+ *
  * Copyright (c) 1982, 1986, 1993, 1994
  *	The Regents of the University of California.  All rights reserved.
  *
diff --git a/newlib/libc/sys/rtems/include/sys/_sockaddr_storage.h b/newlib/libc/sys/rtems/include/sys/_sockaddr_storage.h
index 97af76c4e..333136e3a 100644
--- a/newlib/libc/sys/rtems/include/sys/_sockaddr_storage.h
+++ b/newlib/libc/sys/rtems/include/sys/_sockaddr_storage.h
@@ -1,4 +1,6 @@
 /*-
+ * SPDX-License-Identifier: BSD-3-Clause
+ *
  * Copyright (c) 1982, 1985, 1986, 1988, 1993, 1994
  *	The Regents of the University of California.  All rights reserved.
  *
diff --git a/newlib/libc/sys/rtems/include/sys/_termios.h b/newlib/libc/sys/rtems/include/sys/_termios.h
index eb55bb377..16928a813 100644
--- a/newlib/libc/sys/rtems/include/sys/_termios.h
+++ b/newlib/libc/sys/rtems/include/sys/_termios.h
@@ -1,4 +1,6 @@
 /*-
+ * SPDX-License-Identifier: BSD-3-Clause
+ *
  * Copyright (c) 1988, 1989, 1993, 1994
  *	The Regents of the University of California.  All rights reserved.
  *
diff --git a/newlib/libc/sys/rtems/include/sys/filio.h b/newlib/libc/sys/rtems/include/sys/filio.h
index 471235a88..60675fb50 100644
--- a/newlib/libc/sys/rtems/include/sys/filio.h
+++ b/newlib/libc/sys/rtems/include/sys/filio.h
@@ -1,4 +1,6 @@
 /*-
+ * SPDX-License-Identifier: BSD-3-Clause
+ *
  * Copyright (c) 1982, 1986, 1990, 1993, 1994
  *	The Regents of the University of California.  All rights reserved.
  * (c) UNIX System Laboratories, Inc.
diff --git a/newlib/libc/sys/rtems/include/sys/ioccom.h b/newlib/libc/sys/rtems/include/sys/ioccom.h
index 2c0e9ee71..34ea1e16d 100644
--- a/newlib/libc/sys/rtems/include/sys/ioccom.h
+++ b/newlib/libc/sys/rtems/include/sys/ioccom.h
@@ -1,4 +1,6 @@
 /*-
+ * SPDX-License-Identifier: BSD-3-Clause
+ *
  * Copyright (c) 1982, 1986, 1990, 1993, 1994
  *	The Regents of the University of California.  All rights reserved.
  *
diff --git a/newlib/libc/sys/rtems/include/sys/ioctl.h b/newlib/libc/sys/rtems/include/sys/ioctl.h
index 5eeeb049a..f2217cfc1 100644
--- a/newlib/libc/sys/rtems/include/sys/ioctl.h
+++ b/newlib/libc/sys/rtems/include/sys/ioctl.h
@@ -1,4 +1,6 @@
 /*-
+ * SPDX-License-Identifier: BSD-3-Clause
+ *
  * Copyright (c) 1982, 1986, 1990, 1993, 1994
  *	The Regents of the University of California.  All rights reserved.
  * (c) UNIX System Laboratories, Inc.
diff --git a/newlib/libc/sys/rtems/include/sys/mman.h b/newlib/libc/sys/rtems/include/sys/mman.h
index c099e2242..b2fad0e47 100644
--- a/newlib/libc/sys/rtems/include/sys/mman.h
+++ b/newlib/libc/sys/rtems/include/sys/mman.h
@@ -1,4 +1,6 @@
 /*-
+ * SPDX-License-Identifier: BSD-3-Clause
+ *
  * Copyright (c) 1982, 1986, 1993
  *	The Regents of the University of California.  All rights reserved.
  *
diff --git a/newlib/libc/sys/rtems/include/sys/socket.h b/newlib/libc/sys/rtems/include/sys/socket.h
index 7c42eb5ce..345eaa83f 100644
--- a/newlib/libc/sys/rtems/include/sys/socket.h
+++ b/newlib/libc/sys/rtems/include/sys/socket.h
@@ -1,4 +1,6 @@
 /*-
+ * SPDX-License-Identifier: BSD-3-Clause
+ *
  * Copyright (c) 1982, 1985, 1986, 1988, 1993, 1994
  *	The Regents of the University of California.  All rights reserved.
  *
diff --git a/newlib/libc/sys/rtems/include/sys/sockio.h b/newlib/libc/sys/rtems/include/sys/sockio.h
index 185e46cba..a81a563a9 100644
--- a/newlib/libc/sys/rtems/include/sys/sockio.h
+++ b/newlib/libc/sys/rtems/include/sys/sockio.h
@@ -1,4 +1,6 @@
 /*-
+ * SPDX-License-Identifier: BSD-3-Clause
+ *
  * Copyright (c) 1982, 1986, 1990, 1993, 1994
  *	The Regents of the University of California.  All rights reserved.
  *
diff --git a/newlib/libc/sys/rtems/include/sys/syslog.h b/newlib/libc/sys/rtems/include/sys/syslog.h
index 8a3738daa..7e4ac004a 100644
--- a/newlib/libc/sys/rtems/include/sys/syslog.h
+++ b/newlib/libc/sys/rtems/include/sys/syslog.h
@@ -1,4 +1,6 @@
 /*-
+ * SPDX-License-Identifier: BSD-3-Clause
+ *
  * Copyright (c) 1982, 1986, 1988, 1993
  *	The Regents of the University of California.  All rights reserved.
  *
diff --git a/newlib/libc/sys/rtems/include/sys/ttycom.h b/newlib/libc/sys/rtems/include/sys/ttycom.h
index dec86206c..770985111 100644
--- a/newlib/libc/sys/rtems/include/sys/ttycom.h
+++ b/newlib/libc/sys/rtems/include/sys/ttycom.h
@@ -1,4 +1,6 @@
 /*-
+ * SPDX-License-Identifier: BSD-3-Clause
+ *
  * Copyright (c) 1982, 1986, 1990, 1993, 1994
  *	The Regents of the University of California.  All rights reserved.
  * (c) UNIX System Laboratories, Inc.
diff --git a/newlib/libc/sys/rtems/include/sys/ttydefaults.h b/newlib/libc/sys/rtems/include/sys/ttydefaults.h
index 29464d03a..63cca13b6 100644
--- a/newlib/libc/sys/rtems/include/sys/ttydefaults.h
+++ b/newlib/libc/sys/rtems/include/sys/ttydefaults.h
@@ -1,4 +1,6 @@
 /*-
+ * SPDX-License-Identifier: BSD-3-Clause
+ *
  * Copyright (c) 1982, 1986, 1993
  *	The Regents of the University of California.  All rights reserved.
  * (c) UNIX System Laboratories, Inc.
diff --git a/newlib/libc/sys/rtems/include/sys/uio.h b/newlib/libc/sys/rtems/include/sys/uio.h
index a01492ade..6d3c3cce2 100644
--- a/newlib/libc/sys/rtems/include/sys/uio.h
+++ b/newlib/libc/sys/rtems/include/sys/uio.h
@@ -1,4 +1,6 @@
 /*-
+ * SPDX-License-Identifier: BSD-3-Clause
+ *
  * Copyright (c) 1982, 1986, 1993, 1994
  *	The Regents of the University of California.  All rights reserved.
  *
diff --git a/newlib/libc/sys/rtems/include/sys/un.h b/newlib/libc/sys/rtems/include/sys/un.h
index df6d78381..976a81a63 100644
--- a/newlib/libc/sys/rtems/include/sys/un.h
+++ b/newlib/libc/sys/rtems/include/sys/un.h
@@ -1,4 +1,6 @@
 /*-
+ * SPDX-License-Identifier: BSD-3-Clause
+ *
  * Copyright (c) 1982, 1986, 1993
  *	The Regents of the University of California.  All rights reserved.
  *