diff --git a/build_image.sh b/build_image.sh
index 254bc4d930..3a14d8f337 100755
--- a/build_image.sh
+++ b/build_image.sh
@@ -211,7 +211,8 @@ SUITE2="$FLAGS_suite2"
 CHROMEOS_OFFICIAL="$CHROMEOS_OFFICIAL"
 EOF
 # Also export ChromeOS version strings
-set | grep "CHROMEOS_VERSION" >> $CUST_OPTS
+set | grep "^CHROMEOS_VERSION" >> $CUST_OPTS
+echo CHROMEOS_REVISION=$CHROMEOS_REVISION >> $CUST_OPTS
 
 # Run the setup script
 sudo chroot "$ROOT_FS_DIR" "${ROOTFS_SETUP_DIR}/${ROOTFS_CUSTOMIZE_SCRIPT}"