diff --git a/build_gpt.sh b/build_gpt.sh
index 0b7edda064..b0d77228ae 100755
--- a/build_gpt.sh
+++ b/build_gpt.sh
@@ -25,6 +25,8 @@ DEFINE_string arm_extra_bootargs "" \
   "Additional command line options to pass to the ARM kernel."
 DEFINE_boolean recovery $FLAGS_FALSE \
   "Build GPT for a recovery image. Default: False."
+DEFINE_integer rootfs_partition_size 1024 \
+  "rootfs parition size in MBs."
 
 # Usage.
 FLAGS_HELP=$(cat <<EOF
@@ -115,7 +117,7 @@ fi
 # Create the GPT. This has the side-effect of setting some global vars
 # describing the partition table entries (see the comments in the source).
 install_gpt $OUTDEV $ROOTFS_IMG $KERNEL_IMG $STATEFUL_IMG $PMBRCODE $ESP_IMG \
-    false $FLAGS_recovery
+    false $FLAGS_recovery $FLAGS_rootfs_partition_size 
 
 if [[ "$ARCH" = "arm" ]]; then
   # assume /dev/mmcblk1. we could not get this from ${OUTDEV}
diff --git a/build_image b/build_image
index 17afa28d2e..4d05786608 100755
--- a/build_image
+++ b/build_image
@@ -46,6 +46,10 @@ DEFINE_string arm_extra_bootargs "" \
   "Additional command line options to pass to the ARM kernel."
 DEFINE_boolean recovery $FLAGS_FALSE \
   "Build a recovery image. Default: False."
+DEFINE_integer rootfs_partition_size 1024 \
+  "rootfs parition size in MBs."
+DEFINE_integer rootfs_size 720 \
+  "rootfs filesystem size in MBs."
 
 # Parse command line.
 FLAGS "$@" || exit 1
@@ -60,6 +64,11 @@ if [ -z "$FLAGS_board" ] ; then
   exit 1
 fi
 
+if [ "$FLAGS_rootfs_size" -gt "$FLAGS_rootfs_partition_size" ] ; then
+  error "rootfs (${FLAGS_rootfs_size} MB) is bigger than partition (${FLAGS_rootfs_partition_size} MB)."
+  exit 1
+fi
+
 # Determine build version.
 . "${SCRIPTS_DIR}/chromeos_version.sh"
 
@@ -274,7 +283,7 @@ fi
 if [[ $FLAGS_factory_install -eq ${FLAGS_TRUE} ]] ; then
   ROOT_SIZE_BYTES=$((1024 * 1024 * 300))
 else
-  ROOT_SIZE_BYTES=$((1024 * 1024 * 720))
+  ROOT_SIZE_BYTES=$((1024 * 1024 * ${FLAGS_rootfs_size}))
 fi
 
 dd if=/dev/zero of="$ROOT_FS_IMG" bs=1 count=1 seek=$((ROOT_SIZE_BYTES - 1))
@@ -497,6 +506,7 @@ ${SCRIPTS_DIR}/build_gpt.sh \
   --arch=${ARCH} \
   --board=${FLAGS_board} \
   --arm_extra_bootargs="${FLAGS_arm_extra_bootargs}" \
+  --rootfs_partition_size=${FLAGS_rootfs_partition_size} \
   ${RECOVERY} \
   "${OUTPUT_DIR}" \
   "${OUTPUT_IMG}"