diff --git a/README.md b/README.md
index 7075049..4679874 100644
--- a/README.md
+++ b/README.md
@@ -50,6 +50,13 @@ On Fedora:
        yum install perl-Device-SerialPort
        yum install perl-YAML
 
+On Mac using MacPorts:
+
+       sudo port install p5-device-serialport
+       sudo port install p5-YAML
+
+      and use /opt/local/bin/perl5 instead of /usr/bin/perl
+
 On other systems:
 
        cpanm Device::SerialPort
@@ -120,6 +127,8 @@ The following are the list of changes that I have made or merged in this fork. H
 - Added sketch size verification. (https://github.com/fornellas)
 - Show original line number for error messages (https://github.com/WizenedEE)
 - Removed -w from CPPFLAGS to show warnings (https://github.com/gaftech)
+- Changed shebang to use /usr/bin/env (https://github.com/anm)
+- set USB_VID and USB_PID only for leonardo boards(https://github.com/alohr)
 
 ## Know Issues
 - Because of the way the makefile is structured, the configuration parameters gets printed twice. 
diff --git a/arduino-mk/Arduino.mk b/arduino-mk/Arduino.mk
index c38a22e..c630169 100644
--- a/arduino-mk/Arduino.mk
+++ b/arduino-mk/Arduino.mk
@@ -145,6 +145,8 @@
 #   		- Added sketch size verification. (https://github.com/fornellas)
 #   		- Show original line number for error messages (https://github.com/WizenedEE)
 #   		- Removed -w from CPPFLAGS to show warnings (https://github.com/gaftech)
+#   		- Changed shebang to use /usr/bin/env (https://github.com/anm)
+#   		- set USB_VID and USB_PID only for leonardo boards(https://github.com/alohr)
 #
 ########################################################################
 #
@@ -554,6 +556,7 @@ ifndef F_CPU
     F_CPU = $(shell $(PARSE_BOARD_CMD) $(BOARD_TAG) build.f_cpu)
 endif
 
+ifeq ($(VARIANT),leonardo) 
 # USB IDs for the Leonardo
 ifndef USB_VID
 USB_VID = $(shell $(PARSE_BOARD_CMD) $(BOARD_TAG) build.vid)
@@ -562,6 +565,7 @@ endif
 ifndef USB_PID
 USB_PID = $(shell $(PARSE_BOARD_CMD) $(BOARD_TAG) build.pid)
 endif
+endif
 
 # normal programming info
 ifndef AVRDUDE_ARD_PROGRAMMER