diff --git a/cli_classic.c b/cli_classic.c
index 7f6887c..5bdfa01 100644
--- a/cli_classic.c
+++ b/cli_classic.c
@@ -275,6 +275,9 @@
 			}
 			break;
 		case OPTION_FLASH_CONTENTS:
+			if (referencefile)
+				cli_classic_abort_usage("Error: --flash-contents specified more than once."
+							"Aborting.\n");
 			referencefile = strdup(optarg);
 			break;
 		case OPTION_FLASH_NAME: