diff --git a/HISTORY.md b/HISTORY.md
index 3b53c83..a3611c8 100644
--- a/HISTORY.md
+++ b/HISTORY.md
@@ -12,6 +12,7 @@ I tried to give credit whenever possible. If I have missed anyone, kindly add it
 - Fix: ARDUINO_VERSION can cope with the longer 1.6.10 version string (issue #444) (https://github.com/sej7278)
 - Fix: Changed PARSE_BOARD to handle colons in e.g. CORE or VARIANT (issue #461) (https://github.com/sej7278)
 - Tweak: Documentation for Windows updated to include installation of PySerial (https://github.com/sovcik) 
+- FIX: Changed Teensy.mk to support Arduino 1.6.12 and Teensyduino 1.30 (issues #383 , #431) (https://github.com/georgeharker)
 
 ### 1.5.1 (Debian version: 1.5-3) (2016-02-22)
 
diff --git a/Teensy.mk b/Teensy.mk
index edbdbb4..9e986a8 100644
--- a/Teensy.mk
+++ b/Teensy.mk
@@ -46,7 +46,12 @@ ifndef PARSE_TEENSY
     PARSE_TEENSY = $(shell grep -v "^\#" "$(BOARDS_TXT)" | grep $(1).$(2) | cut -d = -f 2,3 )
 endif
 
+# if boards.txt gets modified, look there, else hard code it
 ARCHITECTURE  = $(call PARSE_TEENSY,$(BOARD_TAG),build.architecture)
+ifeq ($(strip $(MONITOR_PORT)),)
+	ARCHITECTURE = arm
+endif
+
 AVR_TOOLS_DIR = $(call dir_if_exists,$(ARDUINO_DIR)/hardware/tools/$(ARCHITECTURE))
 
 # define plaform lib dir ignoring teensy's oversight on putting it all in avr