diff --git a/platform/sky/Makefile.common b/platform/sky/Makefile.common
index 492a7371a..c6bb0dc93 100644
--- a/platform/sky/Makefile.common
+++ b/platform/sky/Makefile.common
@@ -58,27 +58,49 @@ ifeq ($(HOST_OS),Windows)
   CMOTES = $(shell $(MOTELIST) | grep COM | \
      cut -f 4 -d \  | \
      perl -ne 'print $$1 . " " if(/COM(\d+)/);')
-endif
-
-# If we are not running under Windows, we assume Linux
-ifndef MOTELIST
-  USBDEVPREFIX=
-  SERIALDUMP = $(CONTIKI)/tools/sky/serialdump-linux
-  MOTELIST = $(CONTIKI)/tools/sky/motelist-linux
-  TMOTE_BSL_FILE = tmote-bsl-linux
-  TMOTE_BSL=$(if $(wildcard $(CONTIKI)/tools/sky/$(TMOTE_BSL_FILE)),1,0)
-  ifeq ($(TMOTE_BSL), 1)
-    PATH := $(PATH):$(CONTIKI)/tools/sky
-    BSL =  $(CONTIKI)/tools/sky/$(TMOTE_BSL_FILE)
-    NUMPAR = 1
-  else
-    BSL = $(CONTIKI)/tools/sky/msp430-bsl-linux --telosb
-    BSL_FILETYPE = -I
+else
+ifeq ($(HOST_OS),Darwin)
+  ifndef MOTELIST
+    USBDEVPREFIX=
+    SERIALDUMP = $(CONTIKI)/tools/sky/serialdump-linux
+    MOTELIST = $(CONTIKI)/tools/sky/motelist-macos
+    TMOTE_BSL_FILE = tmote-bsl-linux
+    TMOTE_BSL=$(if $(wildcard $(CONTIKI)/tools/sky/$(TMOTE_BSL_FILE)),1,0)
+    ifeq ($(TMOTE_BSL), 1)
+      PATH := $(PATH):$(CONTIKI)/tools/sky
+      BSL =  $(CONTIKI)/tools/sky/$(TMOTE_BSL_FILE)
+      NUMPAR = 1
+    else
+      BSL = $(CONTIKI)/tools/sky/msp430-bsl-linux --telosb
+      BSL_FILETYPE = -I
+    endif
+    MOTES = $(shell $(MOTELIST) 2>&- | grep usbserial | \
+       cut -f 4 -d \  | \
+       perl -ne 'print $$1 . " " if(m-(/dev/[\w+\.\-]+)-);')
+    CMOTES=$(MOTES)
   endif
-  MOTES = $(shell $(MOTELIST) 2>&- | grep USB | \
-     cut -f 4 -d \  | \
-     perl -ne 'print $$1 . " " if(m-(/dev/\w+)-);')
-  CMOTES=$(MOTES)
+else
+  # Else we assume Linux
+  ifndef MOTELIST
+    USBDEVPREFIX=
+    SERIALDUMP = $(CONTIKI)/tools/sky/serialdump-linux
+    MOTELIST = $(CONTIKI)/tools/sky/motelist-linux
+    TMOTE_BSL_FILE = tmote-bsl-linux
+    TMOTE_BSL=$(if $(wildcard $(CONTIKI)/tools/sky/$(TMOTE_BSL_FILE)),1,0)
+    ifeq ($(TMOTE_BSL), 1)
+      PATH := $(PATH):$(CONTIKI)/tools/sky
+      BSL =  $(CONTIKI)/tools/sky/$(TMOTE_BSL_FILE)
+      NUMPAR = 1
+    else
+      BSL = $(CONTIKI)/tools/sky/msp430-bsl-linux --telosb
+      BSL_FILETYPE = -I
+    endif
+    MOTES = $(shell $(MOTELIST) 2>&- | grep USB | \
+       cut -f 4 -d \  | \
+       perl -ne 'print $$1 . " " if(m-(/dev/[\w+\.\-]+)-);')
+    CMOTES=$(MOTES)
+  endif
+endif
 endif
 
 motelist: sky-motelist
@@ -91,7 +113,7 @@ sky-motes:
 ifdef MOTE
 %.upload: %.ihex
 	cp $< $(IHEXFILE)
-	$(MAKE) sky-u.$(subst /,-,$(word $(MOTE), $(MOTES)))
+	$(MAKE) sky-u.$(subst /,_,$(word $(MOTE), $(MOTES)))
 else # MOTE
 %.upload: %.ihex
 	cp $< $(IHEXFILE)
@@ -103,7 +125,7 @@ ifdef FILE
 	@echo Uploading $(FILE)
 	cp $(FILE) $(IHEXFILE)
 ifdef MOTE
-	$(MAKE) sky-u.$(subst /,-,$(word $(MOTE), $(MOTES)))
+	$(MAKE) sky-u.$(subst /,_,$(word $(MOTE), $(MOTES)))
 else # MOTE
 	$(MAKE) sky-reset sky-upload
 endif # MOTE
@@ -114,25 +136,25 @@ endif
 sky-upload: sky-reset
 	$(MAKE) -j $(NUMPAR) sky-upload-sequence
 
-sky-upload-sequence:	$(foreach PORT, $(MOTES), sky-u.$(subst /,-,$(PORT)))
+sky-upload-sequence:	$(foreach PORT, $(MOTES), sky-u.$(subst /,_,$(PORT)))
 	@echo Done
 
 sky-reset:
 	$(MAKE) -k -j $(NUMPAR) sky-reset-sequence
 
-sky-reset-sequence:	$(foreach PORT, $(MOTES), sky-r.$(subst /,-,$(PORT)))
+sky-reset-sequence:	$(foreach PORT, $(MOTES), sky-r.$(subst /,_,$(PORT)))
 	@echo Done
 
 sky-u.%:
-	@echo +++++ Erasing $(subst -,/,$*); \
-	$(BSL) -c $(subst -,/,$*) -e && sleep 2 ; \
-	echo +++++ Programming $(subst -,/,$*) ; \
-	$(BSL) -c $(subst -,/,$*) $(BSL_FILETYPE) -p $(IHEXFILE) && sleep 2 ; \
-	echo +++++ Resetting $(subst -,/,$*) ; \
-	$(BSL) -c $(subst -,/,$*) -r
+	@echo +++++ Erasing $(subst _,/,$*); \
+	$(BSL) -c $(subst _,/,$*) -e && sleep 2 ; \
+	echo +++++ Programming $(subst _,/,$*) ; \
+	$(BSL) -c $(subst _,/,$*) $(BSL_FILETYPE) -p $(IHEXFILE) && sleep 2 ; \
+	echo +++++ Resetting $(subst _,/,$*) ; \
+	$(BSL) -c $(subst _,/,$*) -r
 
 sky-r.%:
-	$(BSL) -c $(subst -,/,$*) -r
+	$(BSL) -c $(subst _,/,$*) -r
 
 sizeplot:
 	msp430-size $(OBJECTDIR)/*.o | $(CONTIKI)/tools/sky/check-size > size-data
diff --git a/tools/sky/motelist-macos b/tools/sky/motelist-macos
new file mode 100755
index 000000000..ee5618b1e
--- /dev/null
+++ b/tools/sky/motelist-macos
@@ -0,0 +1,75 @@
+#!/usr/bin/perl -w
+use strict;
+
+my $help = <<'EOF';
+usage: motelist [options]
+
+options:
+  -h  display this help
+  -c  compact format, not pretty but easier for parsing
+EOF
+
+my %Opt = (
+  compact => 0,
+  dev_prefix => [ "/dev/tty.usbserial-" ],
+);
+
+while (@ARGV) {
+  last unless $ARGV[0] =~ /^-/;
+  my $opt = shift @ARGV;
+  if( $opt eq "-h" ) { print "$help\n"; exit 0; }
+  elsif( $opt eq "-c" ) { $Opt{compact} = 1; }
+  else { print STDERR "$help\nerror, unknown command line option $opt\n"; exit 1; }
+}
+
+print_motelist( scan_dev() );
+
+#
+#  Scan /dev for tty.usbserial-*
+#
+sub  scan_dev {
+  my @devs;
+  foreach (`ls /dev/tty.usbserial-* 2>&1`) {
+    my($dev, $serial) = /(\/dev\/tty.usbserial-(\S+))/;
+    if ($serial ne "*:") {
+      my $d;
+      $d->{"InfoSerial"} = $serial;
+      $d->{"SerialDevName"} = $dev;
+      push(@devs, $d);
+    }
+  }
+  return @devs;
+}
+
+
+#
+#  Print motelist
+#
+sub print_motelist {
+  my @devs = @_;
+
+  #  If none were found, quit
+  if( @devs == 0 ) {
+    print "No devices found.\n";
+    return;
+  }
+
+  #  Print a header
+  if( !$Opt{compact} ) {
+    print << "EOF" unless $Opt{compact};
+Reference  Device                      Description
+---------- --------------------------- ---------------------------------------
+EOF
+  }
+
+  #  Print the usb information
+  for my $dev (@devs) {
+    my $desc = "(none)";
+    my @output = ( $dev->{"InfoSerial"}, $dev->{"SerialDevName"}, $desc );
+    if( $Opt{compact} ) {
+      print join(",",@output) . "\n";
+    } else {
+      printf( "%-10s %-27s %s\n", @output );
+    }
+  }
+}