diff --git a/sys/boot/i386/gptboot/gptldr.S b/sys/boot/i386/gptboot/gptldr.S
index 6dbe0acd9206..4471a3a3835c 100644
--- a/sys/boot/i386/gptboot/gptldr.S
+++ b/sys/boot/i386/gptboot/gptldr.S
@@ -28,6 +28,8 @@
  * SUCH DAMAGE.
  *
  * $FreeBSD$
+ *
+ * Partly from: src/sys/boot/i386/boot2/boot1.S 1.31
  */
 
 /* Memory Locations */
diff --git a/sys/boot/i386/pmbr/pmbr.s b/sys/boot/i386/pmbr/pmbr.s
index 217ccfbd193a..8acdef23dfeb 100644
--- a/sys/boot/i386/pmbr/pmbr.s
+++ b/sys/boot/i386/pmbr/pmbr.s
@@ -28,6 +28,8 @@
 # SUCH DAMAGE.
 #
 # $FreeBSD$
+#
+# Partly from: src/sys/boot/i386/mbr/mbr.s 1.7
 
 # A 512 byte PMBR boot manager that looks for a FreeBSD boot GPT partition
 # and boots it.