diff --git a/usb_disk/media_internal.c b/usb_disk/media_internal.c
index 16df1affe..4591b6287 100644
--- a/usb_disk/media_internal.c
+++ b/usb_disk/media_internal.c
@@ -4,6 +4,7 @@
 
 //#include "pauls_ugly_debug.h"
 
+// This file is used only for Teensy 2.0 and Teensy++ 2.0
 
 inline uint32_t media_size(void);
 void media_init(void);
diff --git a/usb_disk/media_sdcard.c b/usb_disk/media_sdcard.c
index 48a5106f1..9de68b96f 100644
--- a/usb_disk/media_sdcard.c
+++ b/usb_disk/media_sdcard.c
@@ -4,6 +4,8 @@
 
 //#include "pauls_ugly_debug.h"
 
+// This file is used only for Teensy 2.0 and Teensy++ 2.0
+
 #include "core_pins.h" // for delayMicroseconds
 
 inline uint32_t media_size(void);
diff --git a/usb_disk/usb.c b/usb_disk/usb.c
index f685d523b..feaf2514e 100644
--- a/usb_disk/usb.c
+++ b/usb_disk/usb.c
@@ -21,6 +21,7 @@
  * THE SOFTWARE.
  */
 
+// This file is used only for Teensy 2.0 and Teensy++ 2.0
 
 #include "usb_common.h"
 #include "usb_private.h"
diff --git a/usb_disk/usb_api.cpp b/usb_disk/usb_api.cpp
index 80f1824af..ca7b60b15 100644
--- a/usb_disk/usb_api.cpp
+++ b/usb_disk/usb_api.cpp
@@ -30,7 +30,7 @@
 #include "keylayouts.h"
 #include "wiring.h"
 
-
+// This file is used only for Teensy 2.0 and Teensy++ 2.0
 
 
 // Step #1, decode UTF8 to Unicode code points
diff --git a/usb_flightsim/usb.c b/usb_flightsim/usb.c
index 246665146..35b8aa26e 100644
--- a/usb_flightsim/usb.c
+++ b/usb_flightsim/usb.c
@@ -21,6 +21,7 @@
  * THE SOFTWARE.
  */
 
+// This file is used only for Teensy 2.0 and Teensy++ 2.0
 
 #include "usb_common.h"
 #include "usb_private.h"
diff --git a/usb_flightsim/usb_api.cpp b/usb_flightsim/usb_api.cpp
index 3c7319339..ecbcae920 100644
--- a/usb_flightsim/usb_api.cpp
+++ b/usb_flightsim/usb_api.cpp
@@ -29,6 +29,8 @@
 #include "usb_api.h"
 #include "wiring.h"
 
+// This file is used only for Teensy 2.0 and Teensy++ 2.0
+
 
 FlightSimCommand * FlightSimCommand::first = NULL;
 FlightSimCommand * FlightSimCommand::last = NULL;
diff --git a/usb_hid/usb.c b/usb_hid/usb.c
index 10ff7a6ec..fbdcb607b 100644
--- a/usb_hid/usb.c
+++ b/usb_hid/usb.c
@@ -21,6 +21,7 @@
  * THE SOFTWARE.
  */
 
+// This file is used only for Teensy 2.0 and Teensy++ 2.0
 
 #include "usb_common.h"
 #include "usb_private.h"
diff --git a/usb_hid/usb_api.cpp b/usb_hid/usb_api.cpp
index 232d0fa7b..480a4ef6c 100644
--- a/usb_hid/usb_api.cpp
+++ b/usb_hid/usb_api.cpp
@@ -29,6 +29,7 @@
 #include "usb_api.h"
 #include "wiring.h"
 
+// This file is used only for Teensy 2.0 and Teensy++ 2.0
 
 
 // Step #1, decode UTF8 to Unicode code points
diff --git a/usb_midi/usb.c b/usb_midi/usb.c
index b4467db1b..ff6db54c2 100644
--- a/usb_midi/usb.c
+++ b/usb_midi/usb.c
@@ -21,6 +21,7 @@
  * THE SOFTWARE.
  */
 
+// This file is used only for Teensy 2.0 and Teensy++ 2.0
 
 #include "usb_common.h"
 #include "usb_private.h"
diff --git a/usb_midi/usb_api.cpp b/usb_midi/usb_api.cpp
index 97a7c6774..0c87293d6 100644
--- a/usb_midi/usb_api.cpp
+++ b/usb_midi/usb_api.cpp
@@ -29,6 +29,7 @@
 #include "usb_api.h"
 #include "wiring.h"
 
+// This file is used only for Teensy 2.0 and Teensy++ 2.0
 
 void usb_midi_class::sendSysEx_BufferHasTerm(uint16_t length, const uint8_t *data)
 {
diff --git a/usb_rawhid/usb.c b/usb_rawhid/usb.c
index 59f884f7d..14f3447cd 100644
--- a/usb_rawhid/usb.c
+++ b/usb_rawhid/usb.c
@@ -21,6 +21,7 @@
  * THE SOFTWARE.
  */
 
+// This file is used only for Teensy 2.0 and Teensy++ 2.0
 
 #include "usb_common.h"
 #include "usb_private.h"
diff --git a/usb_rawhid/usb_api.cpp b/usb_rawhid/usb_api.cpp
index 07625c32c..0bc032bc6 100644
--- a/usb_rawhid/usb_api.cpp
+++ b/usb_rawhid/usb_api.cpp
@@ -29,6 +29,8 @@
 #include "usb_api.h"
 #include "wiring.h"
 
+// This file is used only for Teensy 2.0 and Teensy++ 2.0
+
 
 int usb_rawhid_class::available(void)
 {
diff --git a/usb_serial/usb.c b/usb_serial/usb.c
index 0188b1a21..95deca9d1 100644
--- a/usb_serial/usb.c
+++ b/usb_serial/usb.c
@@ -21,6 +21,7 @@
  * THE SOFTWARE.
  */
 
+// This file is used only for Teensy 2.0 and Teensy++ 2.0
 
 #include "usb_common.h"
 #include "usb_private.h"
diff --git a/usb_serial/usb_api.cpp b/usb_serial/usb_api.cpp
index ede8265bb..696458bbf 100644
--- a/usb_serial/usb_api.cpp
+++ b/usb_serial/usb_api.cpp
@@ -28,6 +28,8 @@
 #include "usb_api.h"
 #include "wiring.h"
 
+// This file is used only for Teensy 2.0 and Teensy++ 2.0
+
 // Public Methods //////////////////////////////////////////////////////////////
 
 void usb_serial_class::begin(long speed)
diff --git a/usb_serial_hid/usb.c b/usb_serial_hid/usb.c
index 288e27c07..76dbb4283 100644
--- a/usb_serial_hid/usb.c
+++ b/usb_serial_hid/usb.c
@@ -21,6 +21,7 @@
  * THE SOFTWARE.
  */
 
+// This file is used only for Teensy 2.0 and Teensy++ 2.0
 
 #include "usb_common.h"
 #include "usb_private.h"
diff --git a/usb_serial_hid/usb_api.cpp b/usb_serial_hid/usb_api.cpp
index 857d231d5..89748ad3a 100644
--- a/usb_serial_hid/usb_api.cpp
+++ b/usb_serial_hid/usb_api.cpp
@@ -28,6 +28,8 @@
 #include "usb_api.h"
 #include "wiring.h"
 
+// This file is used only for Teensy 2.0 and Teensy++ 2.0
+
 // Public Methods //////////////////////////////////////////////////////////////
 
 void usb_serial_class::begin(long speed)