diff --git a/etc/defaults/rc.conf b/etc/defaults/rc.conf
index 13b0d27528da..f4fa7a8846df 100644
--- a/etc/defaults/rc.conf
+++ b/etc/defaults/rc.conf
@@ -21,6 +21,8 @@
 ###  Important initial Boot-time options  ####################
 ##############################################################
 
+# rc_debug can't be set here without interferring with rc.subr's setting it
+# when the kenv variable rc.debug is set.
 #rc_debug="NO"		# Set to YES to enable debugging output from rc.d
 rc_info="NO"		# Enables display of informational messages at boot.
 rc_startmsgs="YES" 	# Show "Starting foo:" messages at boot
diff --git a/etc/rc.subr b/etc/rc.subr
index 3630af6acd74..340ef4eb869c 100644
--- a/etc/rc.subr
+++ b/etc/rc.subr
@@ -2120,7 +2120,8 @@ _echoonce()
 }
 
 # If the loader env variable rc.debug is set, turn on debugging. rc.conf will
-# still override this, but /etc/defaults/rc.conf.a
+# still override this, but /etc/defaults/rc.conf can't unconditionally set this
+# since it would undo what we've done here.
 if kenv -q rc.debug > /dev/null ; then
 	rc_debug=YES
 fi