diff --git a/core/Makefile b/core/Makefile
index 628a8de..a2b9391 100644
--- a/core/Makefile
+++ b/core/Makefile
@@ -720,8 +720,12 @@
 		$(INSTALLED_SYSTEMTARBALL_TARGET)
 endef
 
+ifndef SYSTEM_TARBALL_FORMAT
+    SYSTEM_TARBALL_FORMAT := bz2
+endif
+
 system_tar := $(PRODUCT_OUT)/system.tar
-INSTALLED_SYSTEMTARBALL_TARGET := $(system_tar).bz2
+INSTALLED_SYSTEMTARBALL_TARGET := $(system_tar).$(SYSTEM_TARBALL_FORMAT)
 $(INSTALLED_SYSTEMTARBALL_TARGET): PRIVATE_SYSTEM_TAR := $(system_tar)
 $(INSTALLED_SYSTEMTARBALL_TARGET): $(FS_GET_STATS) $(INTERNAL_SYSTEMIMAGE_FILES)
 	$(build-systemtarball-target)
diff --git a/core/main.mk b/core/main.mk
index 8a86aeb..8c87c74 100644
--- a/core/main.mk
+++ b/core/main.mk
@@ -35,7 +35,7 @@
 $(warning ********************************************************************************)
 $(warning *  You are using version $(MAKE_VERSION) of make.)
 $(warning *  You must upgrade to version 3.81 or greater.)
-$(warning *  see http://source.android.com/download)
+$(warning *  see http://source.android.com/source/download.html)
 $(warning ********************************************************************************)
 $(error stopping)
 endif
@@ -109,7 +109,7 @@
 $(info The correct version is: 1.6.)
 $(info $(space))
 $(info Please follow the machine setup instructions at)
-$(info $(space)$(space)$(space)$(space)http://source.android.com/download)
+$(info $(space)$(space)$(space)$(space)http://source.android.com/source/download.html)
 $(info ************************************************************)
 $(error stop)
 endif
@@ -125,7 +125,7 @@
 $(info The correct version is: 1.6.)
 $(info $(space))
 $(info Please follow the machine setup instructions at)
-$(info $(space)$(space)$(space)$(space)http://source.android.com/download)
+$(info $(space)$(space)$(space)$(space)http://source.android.com/source/download.html)
 $(info ************************************************************)
 $(error stop)
 endif
diff --git a/tools/mktarball.sh b/tools/mktarball.sh
index ea1a8ed..3e32006 100755
--- a/tools/mktarball.sh
+++ b/tools/mktarball.sh
@@ -39,7 +39,14 @@
 done
 
 if [ $? -eq 0 ] ; then
-    bzip2 -c ${target_tar} > ${target_tarball}
+    case "${target_tarball}" in
+    *.bz2 )
+        bzip2 -c ${target_tar} > ${target_tarball}
+        ;;
+    *.gz )
+        gzip -c ${target_tar} > ${target_tarball}
+        ;;
+    esac
     success=$?
     [ $success -eq 0 ] || rm -f ${target_tarball}
     rm -f ${target_tar}