diff --git a/tools/cooja/config/external_tools_linux_64.config b/tools/cooja/config/external_tools_linux_64.config
new file mode 100644
index 000000000..943579ba4
--- /dev/null
+++ b/tools/cooja/config/external_tools_linux_64.config
@@ -0,0 +1,42 @@
+PATH_CONTIKI = ../../..
+PATH_COOJA_CORE_RELATIVE = /platform/cooja
+PATH_MAKE = make
+PATH_LINKER = ld
+PATH_AR = ar
+PATH_SHELL = sh
+PATH_C_COMPILER = gcc
+PATH_OBJDUMP=objdump
+OBJDUMP_ARGS=-h
+CMD_GREP_PROCESSES = grep "^PROCESS_THREAD[ ]*([^,]*,[^,]*,[^)]*)" -o -H
+REGEXP_PARSE_PROCESSES = ([^/]*.c):PROCESS_THREAD[ ]*\\(([^,]*),[^,]*,[^)]*\\)
+CMD_GREP_INTERFACES = grep "^SIM_INTERFACE([^,]*," -o -d skip -D skip -H -r
+REGEXP_PARSE_INTERFACES = ([^/]*.c):SIM_INTERFACE\\(([^,]*),
+CMD_GREP_SENSORS = grep "^SENSORS_SENSOR([^,]*," -o -d skip -D skip -H -r
+REGEXP_PARSE_SENSORS = ([^/]*.c):SENSORS_SENSOR\\(([^,]*),
+COMPILER_ARGS = -I'$(JAVA_HOME)/include' -I'$(JAVA_HOME)/include/linux' -fno-builtin-printf -fPIC
+LINK_COMMAND_1 = gcc -I'$(JAVA_HOME)/include' -I'$(JAVA_HOME)/include/linux' -shared -Wl,-Map=$(MAPFILE) -o $(LIBFILE)
+LINK_COMMAND_2 =
+AR_COMMAND_1 = ar rcf $(ARFILE)
+AR_COMMAND_2 = 
+CONTIKI_STANDARD_PROCESSES = sensors_process;etimer_process
+CONTIKI_MAIN_TEMPLATE_FILENAME = contiki_template.c
+CORECOMM_TEMPLATE_FILENAME = corecomm_template.java
+PATH_JAVAC = javac
+DEFAULT_PROJECTDIRS = ../apps/mrm;../apps/mspsim
+
+PARSE_WITH_COMMAND=false
+PARSE_COMMAND=nm -a $(LIBFILE)
+MAPFILE_DATA_START = ^.data[ \t]*0x([0-9A-Fa-f]*)[ \t]*0x[0-9A-Fa-f]*[ \t]*$
+MAPFILE_DATA_SIZE = ^.data[ \t]*0x[0-9A-Fa-f]*[ \t]*0x([0-9A-Fa-f]*)[ \t]*$
+MAPFILE_BSS_START = ^.bss[ \t]*0x([0-9A-Fa-f]*)[ \t]*0x[0-9A-Fa-f]*[ \t]*$
+MAPFILE_BSS_SIZE = ^.bss[ \t]*0x[0-9A-Fa-f]*[ \t]*0x([0-9A-Fa-f]*)[ \t]*$
+MAPFILE_VAR_NAME = ^[ \t]*(0x[0-9A-Fa-f]*)[ \t]*([^ ]*)[ \t]*$
+MAPFILE_VAR_ADDRESS_1 = ^[ \t]*0x([0-9A-Fa-f]*)[ \t]*
+MAPFILE_VAR_ADDRESS_2 = [ \t]*$
+MAPFILE_VAR_SIZE_1 = ^
+MAPFILE_VAR_SIZE_2 = [ \t]*(0x[0-9A-Fa-f]*)[ \t]*[^ ]*[ \t]*$
+COMMAND_VAR_NAME_ADDRESS = ^([0-9A-Fa-f][0-9A-Fa-f]*)[ \t][^Tt][ \t]([^ ._][^ ]*)
+COMMAND_DATA_START = ^([0-9A-Fa-f]*)[ \t]d[ \t].data$
+COMMAND_DATA_END = ^([0-9A-Fa-f]*)[ \t]A[ \t]_edata$
+COMMAND_BSS_START = ^([0-9A-Fa-f]*)[ \t]A[ \t]__bss_start$
+COMMAND_BSS_END = ^([0-9A-Fa-f]*)[ \t]A[ \t]_end$
diff --git a/tools/cooja/java/se/sics/cooja/GUI.java b/tools/cooja/java/se/sics/cooja/GUI.java
index cf54792a3..03a8c4bd7 100644
--- a/tools/cooja/java/se/sics/cooja/GUI.java
+++ b/tools/cooja/java/se/sics/cooja/GUI.java
@@ -24,7 +24,7 @@
  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
  * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  *
- * $Id: GUI.java,v 1.96 2008/12/16 15:10:49 fros4943 Exp $
+ * $Id: GUI.java,v 1.97 2008/12/16 16:15:36 fros4943 Exp $
  */
 
 package se.sics.cooja;
@@ -157,6 +157,12 @@ public class GUI extends Observable {
    */
   public static final String EXTERNAL_TOOLS_LINUX_SETTINGS_FILENAME = "/external_tools_linux.config";
 
+  /**
+   * External tools default Linux/Unix settings filename for 64 bit architectures.
+   * EXPERIMENTAL. Tested on Intel 64-bit Gentoo Linux.
+   */
+  public static final String EXTERNAL_TOOLS_LINUX_64_SETTINGS_FILENAME = "/external_tools_linux_64.config";
+
   /**
    * External tools user settings filename.
    */
@@ -2676,12 +2682,22 @@ public class GUI extends Observable {
    */
   public static void loadExternalToolsDefaultSettings() {
     String osName = System.getProperty("os.name").toLowerCase();
+    String osArch = System.getProperty("os.arch").toLowerCase();
 
-    String filename = GUI.EXTERNAL_TOOLS_LINUX_SETTINGS_FILENAME;
+    String filename = null;
     if (osName.startsWith("win")) {
       filename = GUI.EXTERNAL_TOOLS_WIN32_SETTINGS_FILENAME;
     } else if (osName.startsWith("mac os x")) {
       filename = GUI.EXTERNAL_TOOLS_MACOSX_SETTINGS_FILENAME;
+    } else if (osName.startsWith("linux")) {
+      filename = GUI.EXTERNAL_TOOLS_LINUX_SETTINGS_FILENAME;
+      if (osArch.startsWith("amd64")) {
+        filename = GUI.EXTERNAL_TOOLS_LINUX_64_SETTINGS_FILENAME;
+      }
+    } else {
+      logger.warn("Unknown system: " + osName);
+      logger.warn("Using default linux external tools configuration");
+      filename = GUI.EXTERNAL_TOOLS_LINUX_SETTINGS_FILENAME;
     }
 
     logger.info("Loading external tools user settings from: " + filename);