diff --git a/redfish/update_service/test_redfish_image_upload.robot b/redfish/update_service/test_redfish_image_upload.robot
index 6f1a18d..75ba8a0 100644
--- a/redfish/update_service/test_redfish_image_upload.robot
+++ b/redfish/update_service/test_redfish_image_upload.robot
@@ -9,6 +9,9 @@
 ...                       pnor_nokernel_image.pnor.squashfs.tar
 ...                       pnor_invalid_key.pnor.squashfs.tar
 
+# Refer below document to generate bad firmware images for testing.
+# openbmc/openbmc-test-automation/blob/master/docs/code_update.md#generating-bad-firmware-image-for-testing
+
 # Test Parameters:
 # OPENBMC_HOST         The BMC host name or IP address.
 # OPENBMC_USERNAME     The OS login userid.