diff --git a/build/build.xml b/build/build.xml
index 27b592425..4529f91ea 100644
--- a/build/build.xml
+++ b/build/build.xml
@@ -186,7 +186,7 @@
     <fail message="wrong platform (${os.name})" />
   </target>
   
-  <target name="macosx-build" if="macosx" depends="revision-check, macosx-checkos, subprojects-build" description="Build Mac OS X version">
+  <target name="macosx-build" if="macosx" depends="revision-check, macosx-checkos, subprojects-build, macosx-check-arm-toolchain" description="Build Mac OS X version">
     <mkdir dir="macosx/work" />
     
     <!-- assemble the pde -->
@@ -221,19 +221,6 @@
       <arg value="macosx/dist/tools-universal.zip" />
     </exec>
 
-    <exec executable="unzip">
-      <arg value="-q" />
-      <arg value="-n" />
-      <arg value="-d" />
-      <arg value="macosx/work/Arduino.app/Contents/Resources/Java/hardware/tools/" />
-      <arg value="macosx/dist/CodeSourcery_arm.zip" />
-    </exec>
-
-    <exec executable="mv">
-      <arg value="macosx/work/Arduino.app/Contents/Resources/Java/hardware/tools/CodeSourcery_arm" />
-      <arg value="macosx/work/Arduino.app/Contents/Resources/Java/hardware/tools/g++_arm_none_eabi" />
-    </exec>
-
     <copy todir="macosx/work/Arduino.app/Contents/Resources/Java/hardware/tools/">    
       <fileset file="macosx/dist/bossac" />
     </copy>
@@ -247,6 +234,8 @@
     <antcall target="assemble">
       <param name="target.path" value="macosx/work/Arduino.app/Contents/Resources/Java" />
     </antcall>
+
+    <antcall target="get-arm-toolchain-help" />
   </target>
 
   <target name="macosx-run" depends="macosx-build" description="Run Mac OS X version">
@@ -257,6 +246,40 @@
     <exec executable="macosx/work/Arduino.app/Contents/MacOS/JavaApplicationStub" spawn="false"/>
   </target>
 
+  <target name="macosx-check-arm-toolchain">
+    <available file="macosx/work/Arduino.app/Contents/Resources/Java/hardware/tools/g++_arm_none_eabi" 
+      property="arm_available" />
+    <condition property="arm_not_available">
+      <not>
+        <isset property="arm_available" />
+      </not>
+    </condition>
+  </target>
+
+  <target name="macosx-get-arm-toolchain" depends="macosx-check-arm-toolchain" if="arm_not_available">
+    <!-- Retrieve ARM toolchain... -->
+    <get 
+      src="http://arduino.googlecode.com/files/gcc-arm-none-eabi-4.4.1-2010q1-188-macos.tar.gz"
+      dest="macosx/dist/gcc-arm-none-eabi-4.4.1-2010q1-188-macos.tar.gz"
+      skipexisting="true" verbose="true" />
+    <checksum file="macosx/dist/gcc-arm-none-eabi-4.4.1-2010q1-188-macos.tar.gz" algorithm="sha" 
+      fileext=".sha" verifyproperty="checksum.matches"/>
+    <condition property="checksum.matches.fail">
+      <equals arg1="${checksum.matches}" arg2="false"/>
+    </condition>
+    <fail if="checksum.matches.fail">
+      File gcc-arm-none-eabi-4.4.1-2010q1-188-macos.tar.gz failed checksum. 
+      Please remove "macosx/dist/gcc-arm-none-eabi-4.4.1-2010q1-188-macos.tar.gz" to download it again.
+    </fail>
+
+    <!-- ...and unzip on the destination folder -->
+    <exec executable="tar" output="/dev/null">
+      <arg value="xfz"/>
+      <arg value="macosx/dist/gcc-arm-none-eabi-4.4.1-2010q1-188-macos.tar.gz"/>
+      <arg value="--directory=macosx/work/Arduino.app/Contents/Resources/Java/hardware/tools/"/>
+    </exec>
+  </target>
+
   <target name="macosx-dist" if="macosx" depends="macosx-build" description="Create a downloadable .zip for the Mac OS X version">
     <!-- The ant copy command does not preserve permissions. -->
     <chmod file="macosx/work/Arduino.app/Contents/MacOS/JavaApplicationStub" perm="+x" />
@@ -389,6 +412,9 @@
     <chmod perm="755" file="linux/work/hardware/tools/bossac" />
     <chmod perm="755" file="linux/work/hardware/tools/bossac64" />
 
+    <copy todir="linux/work" file="linux/dist/arduino" />
+    <chmod perm="755" file="linux/work/arduino" />
+
     <antcall target="get-arm-toolchain-help" />
   </target>
 
@@ -438,9 +464,6 @@
       <arg value="linux/dist/gcc-arm-none-eabi-4.4.1-2010q1-188-linux32.tar.gz"/>
       <arg value="--directory=linux/work/hardware/tools"/>
     </exec>
-
-    <copy todir="linux/work" file="linux/dist/arduino" />
-    <chmod perm="755" file="linux/work/arduino" />
   </target>
 
   <target name="linux-dist" depends="build" 
diff --git a/build/macosx/dist/CodeSourcery_arm.zip b/build/macosx/dist/CodeSourcery_arm.zip
deleted file mode 100644
index 032c42943..000000000
Binary files a/build/macosx/dist/CodeSourcery_arm.zip and /dev/null differ
diff --git a/build/macosx/dist/gcc-arm-none-eabi-4.4.1-2010q1-188-macos.tar.gz.sha b/build/macosx/dist/gcc-arm-none-eabi-4.4.1-2010q1-188-macos.tar.gz.sha
new file mode 100644
index 000000000..3b951bb7f
--- /dev/null
+++ b/build/macosx/dist/gcc-arm-none-eabi-4.4.1-2010q1-188-macos.tar.gz.sha
@@ -0,0 +1 @@
+14c554bb9aa9f0d0262a593e7452d33f4babc60d